Olivier Giroud? 'Physical. Very physical.' Mesut Ozil? 'He's in great form. He can always create something, an assist, find a goal.' Aaron Ramsey? 'With his runs, he always gets in the box at the right time.'

Thomas Vermaelen is alert to the damage Arsenal's players can cause Barcelona, as the teams prepare to face off in the Champions League last 16, beginning with Tuesday night's clash at the Emirates. Beyond the obvious attacking stars Vermaelen is wary of some less heralded players. He singles one out in particular.

'I'm impressed with Francis Coquelin. I know him quite well, when I started he was already there, training with us. Even if he wasn't playing in training I found him impressive, so I'm not surprised at all he's doing well. He's a key player for them, helps them keep their shape and gives Arsenal stability.'

Thomas Vermaelen will come up against his former side Arsenal in the Champions League this week

The Barcelona defender has been very impressed by the emergence of Francis Coquelin in the last year

Some Barcelona fans might not recognise Coquelin if he passed them on the street, but Vermaelen knows if he can shut down the Catalans' engine room, becoming a spanner in the works for elite trio Sergio Busquets, Ivan Rakitic and Andres Iniesta, life will become complicated for the current European champions.

Might Luis Enrique and his technical team call on Vermaelen's experience, his five-year history at Arsenal, to find out how best to shoot down the Gunners? He laughs. 'They have so many tactical people to analyse the videos and games and see how Arsenal play, they are all well prepared so they don't need me for that. Maybe they'll ask me about one or two players, because I know them a bit better, but as a team they analyse them thoroughly.'

Catalan eyes were on the Gunners' crucial win over Leicester, which saw the north London side eke back vital points in the race for the Premier League, something they have not won since 2004. Vermaelen backs the 12-year wait to end.

'They're having a good season. They are in the title race. I gave them a big chance at the beginning of the season because I was quite impressed by the way they started,' he says. 'They've dropped a few points against lower teams recently, but that's the English league. Everybody drops points. That will always happen, I remember my time at Arsenal, every weekend you have to fight for the three points. I think they have a good chance to win it.'

Olivier Giroud will be expected to lead the line for the Gunners in the first leg of the Champions League tie

Vermaelen (left) endured a frustrating first season with Barcelona as injury spoiled his 2013-14 campaign

Vermaelen has been impressed by Petr Cech

A crucial component in their bid for glory has been the arrival of a new man between the sticks. New to Arsenal, that is, but not the Premier League—Petr Cech. 'He's great value,' explains the Belgian. 'He's a world class goalkeeper. A strong goalkeeper. He's got a lot of experience, which is what you actually need. They made a good signing.'

The 33-year-old will represent a particular challenge for the Catalans to overcome in this tie, and Vermaelen knows it. 'I heard he's always playing well against Barcelona, so it's going to be difficult,' he says, smiling. But the Czech Republic stopper is no laughing matter for the Barcelona players who have faced him before.

Messi, the man of so many milestones, such perplexing numbers, has not managed to beat the former Chelsea goalkeeper in the Champions League, despite playing against him six times. 'Exactly. But I don't think he [Messi] has that in his mind.'

What Messi has in his mind is hard to know. The Argentine is a mysterious figure, who mostly keeps himself to himself, but not quite enough for Cristiano Ronaldo's liking, with Messi's eternal rival recently hitting out at his close friendship with fellow forwards Neymar and Suarez. Ronaldo said the 'little hugs and kisses' count for nothing and it's what's done on the pitch which is the measure of a man.

Lionel Messi - in action for Barcelona against Las Palmas on Saturday - is yet to score against keeper Cech

The Belgian signed for the Catalans in a £15million deal in August 2014 but he has had little playing time

VERMAELEN CAREER STATS 2003–2009: Ajax 100 games (8 goals) 2009–2014: Arsenal 152 (15) 2014 - present: Barcelona: 16 (1) Honours: Ajax: Eredivisie: 2003–04; KNVB Cup: 2005-06, 2006-07; Johan Cruijff Shield: 2006, 2007 Arsenal: FA Cup: 2013–14 Barcelona: La Liga: 2014–15; Copa del Rey: 2014–15; UEFA Champions League: 2014–15; UEFA Super Cup: 2015; FIFA Club World Cup: 2015 Advertisement

Unfortunately for Ronaldo, most of what we know about Messi is based on what happens on the pitch. He vanquishes teams with little ado, and if he doesn't, the Brazilian and the Uruguayan are ready to step in, like against Las Palmas on Saturday, when their goals helped Barcelona prolong their unbeaten streak to 32 games.

Vermaelen is in no doubt of the five-time Ballon d'Or winner's ability, nor that of the other two South Americans who form world football's most frightening and most prolific frontline. 'They are the three best in the world. Together they are incredible. The goals they score, the way they play.'

The defender thinks going up against them in training every day forces him to raise his level. The other players too. 'What they do on the pitch they do in training as well. For us it's amazing. If you play against the best, you will only get better. You have to improve. We're lucky we can see them every day in training; what they do is special. We're lucky we can see it. You have to wait until it's on the TV, but we can see it every day.'

Vermaelen alongside Aaron Ramsey, Per Mertesacker and Carl Jenkinson during his time with Arsenal

The former Ajax defender played against Barcelona for Arsenal in the Champions League quarter-finals

Of the three strikers he knows Suarez best. Vermaelen played with him at Ajax in Amsterdam, he played against him in the Premier League when the Uruguayan was at Liverpool and the pair were reunited in the summer of 2014 at Barcelona, something the Belgian appreciated. He says: 'We had history at Ajax and it's always nice to see players later in your career.'

Suarez, who has 41 goals this season scored the goal that effectively won Barcelona the Champions League last season, putting them 2-1 up against Juventus, before Neymar's late third sealed victory in Berlin. He also was Manchester City's executioner, scoring both goals as Barcelona beat the English side 2-1 at the Etihad Stadium.

It was a last-16 first leg, like this clash, and if Arsenal are not careful the man who could have joined them for £40m plus one pound in the summer of 2013 may be able to do the same to them. Scoring goals is his business and business is good.

Vermaelen played with Luis Suarez at Ajax in Amsterdam and found him an awkward opponent in England

Javier Mascherano has stood in the way of Vermaelen's path to more regular first-team football in Spain

Gerard Pique frequently partners Mascherano

'Suarez hasn't changed,' points out Vermaelen. 'He's always been competitive like he is now. He's been a similar player but now he plays at a high level. He's improving and fitting in nicely at Barcelona. I'm not surprised at what he's become. Even at Ajax he scored goals and was very clinical with his finishing. The difference is he does it at the highest level now.'

Catalonia and Barcelona is definitely a different world to London and Arsenal, but Vermaelen has not forgotten his old pals. 'Sometimes I'm in contact with Aaron Ramsey and Theo Walcott,' he says. 'I played golf with Aaron and Theo sometimes. He's much better than me! But he practises more.'

While a classic pastime for footballers in England, it turns out there's no culture of it in Spain. Asked if any of his team-mates like to hit the course, Vermaelen responds emphatically. 'No way! I play with people in Sitges (a picturesque town down the coast) sometimes, some people at the course. But I have no time. I have two kids and one is just six months old. I'm very busy.'

His wife Polly, and their children Raff and Ace moved with him to settle down in Barcelona and after his first season was mostly spent on the treatment table and undergoing physiotherapy, things are going better now.

'She [Polly] loves the weather of course. The kids are very happy. The eldest one can play outside every day, he's very active as well,' he says. And Vermaelen too, fit again, is active and is looking to shed the frequent association with injuries that tags along when his name is mentioned.

Having only played one game for Barcelona in his first year there, the final league match of the season, it's understandable people will be sceptical over his fitness. But this year he's featured 17 times and counting.

'Last year [missing most of the season] was a big thing, it's something that will always come up and people will say,' he says. 'But since March, after surgery, I've been fine. I had a small calf injury but everybody has that. Since then it's almost been a year. I'm fine now. I feel good.'

People remain sceptical over the fitness of Vermaelen, who only played in the final game of last season

The defender has returned to fitness this term and has featured in 18 games in all competitions for Barcelona

LIST OF VERMAELEN'S INJURIES Ajax: Ruptured cruciate ligament (missed 109 days and 16 games) Groin strain (missed 34 days and six games) Arsenal: Calf problem (missed 23 days and 4 games) Achilles tendon problem (missed 233 days and 51 games), Achilles tendon surgery (missed 50 days and 11 games) Two separate malleolar injuries (missed 21 days and 4 games) A fatigue fracture (missed 62 days and 5 games) Knee problem (missed 60 days and 12 games) Thigh muscle strain (missed 60 days and 18 games) Barcelona: Thigh muscle strain (missed 176 days, 35 matches) Advertisement

It's tough at Barcelona though, with five centre-backs jostling for position in the squad. Gerard Pique and Javier Mascherano are usually first in line and should start at the Emirates, while Vermaelen seemed to have muscled his way in front of Jeremy Mathieu and Marc Bartra, although Luis Enrique often rotates between them.

Should Vermaelen be doing more to force his way into what is known as the 'gala XI', the team that is selected in the biggest games, like on Tuesday at the Emirates?

'What can you expect if you come to a club like Barcelona?' he argues. 'I see it as a challenge. I'm very happy to be here. There are five players for two positions. You have to fight for it. They're all good players here, there's no weak link in the team. You have to work for it. I'm very happy that I made the decision [to come].'

Sometime there doesn't seem to be much rhyme or reason in how Lucho picks which of the three contenders gets to play, but Vermaelen is happy with the Asturian coach and the communication at the club.

Vermaelen (far right) looks to get on the end of a set-piece during a Champions League group stage match

Luis Enrique is preparing his side to face Arsenal

'I think he's very good in his contact with players. I like that,' says Vermaelen. 'But at the end of the day he makes the decisions, so I feel like he doesn't have to explain all the decisions he makes. He's talking to everybody. He will tell you where you have to improve or not but he can't explain every decision. He's the boss.'

If he does play, there's a chance he could score. As centre-backs go, Vermaelen has been relatively prolific in his career. Earlier this season he netted the winner for Barcelona against Malaga, blasting home from inside the box to earn a 1-0 win.

'Scoring at the Camp Nou is a dream come true,' he says. 'Even playing for this club, is something a lot of players dream of. And I managed to achieve it. Scoring the winning goal was a special moment, something I will never forget.'

And if he found the net against Arsenal? 'I'm not a guy who celebrates too much anyway.' A little celebration? 'Yeah, probably.' He isn't a fan of the muted celebrations trend. 'That's a bit strange, I think it's a bit fake,' he says. 'You have to show respect for who you're playing for as well. I feel like that's not always real.'

He continues, passionate on the topic. 'I play for Barcelona now, so I hope we win. I will never deny I have warm feelings towards Arsenal, it's a club that's been very good to me. I'm very happy that I played there. Sometimes you go different ways and that happens in football. Now I'm at Barcelona and I want to go through.'

Vermaelen was part of the Arsenal squad which won the FA Cup in 2014 after victory over Hull at Wembley

The defender is a self-described calm character, admits he was thrilled when he heard the Champions League draw news, while on a bus in Japan as Barcelona prepared for the Club World Cup. 'I was very excited. Not only because it's my old team, but it's a very attractive game for everybody to watch. Two similar sides that want to play good football. It's a fixture a lot of players have been looking forward to.

'For me it's special, personally. I will go there and see a lot of ex-teammates and the others around the club. I haven't been back there since because I haven't had time. Hopefully I can see a few people there.'

No Whatsapp messages have been flying back and forth between Vermaelen and his old team-mates—'We're all so busy with our schedules'—but he admits that after the clash against Las Palmas, it may begin. Who'll go first? 'Ha! I don't know, let's see what happens.'