Jack Wilshere believes Arsenal have learned the lessons from their chastening Champions League elimination by Barcelona last season and has called on his team-mates to "be a bit nasty" by "getting in the faces" of the Spanish team during a daunting tie, which begins at the Emirates Stadium on Wednesday.

Arsène Wenger's side are set to be boosted by the unexpected availability of Samir Nasri, arguably their most consistently impressive player this season, with the France international having recovered from hamstring damage sustained in the FA Cup fourth-round win over Huddersfield. His return would add to Arsenal's attacking options, though Wilshere and his team-mates will be just as intent on nullifying a Barça team who have scored 71 times in La Liga already this campaign and won 6-3 on aggregate in last year's quarter-final.

"I was at the Emirates Stadium for the first game against Barcelona last season and they were brilliant, especially in that first half," said Wilshere. "I was in Bolton [on loan] for the second match and watched on television but I remember we basically played our game, passing it around. This year we have to get in their faces and show them what we're all about. When we have the ball, we've got to keep it as well as they can. We've got to change our game a bit to play against Barcelona – we'll learn from last year, but we need to get in their faces and, if you like, be a bit nasty, in a footballing sense, to get the ball back.

"We have to press them as a team – there's no point just one of us going after them, so we have to close them down as a team and get the ball back from them. But we'll go into the game on Wednesday looking for the win still. It's important we get that to take to their place for the return match."

Although the teenage midfielder acknowledged a need to tweak the team's approach, Wenger retains faith that his players can unsettle Barcelona by tapping into their own strengths, albeit if they can secure possession for themselves. Arsenal claimed an unlikely 2-2 draw against these opponents in last season's first leg despite being without key players, and with Cesc Fábregas's domestic season ended by the injury picked up converting the hosts' equaliser from the penalty spot. Yet there is strength in depth this time around, with Nasri's potential return particularly timely.

The French midfielder has excelled, scoring 14 times, and had been expected to miss the first leg at the Emirates Stadium. He will have further tests on his hamstring tomorrow and Tuesday before a decision is made, though there is optimism that he will be able to feature against the Spanish champions.

"I will not take a crazy gamble, but physically he is ready," said Wenger. "There is just a risk of him suffering a setback, so we will test him medically and physically. There are other important games coming up – we have Leyton Orient in the FA Cup, and the Carling Cup final, and the return game in Barcelona in three weeks. So it is important not to be stupid.

"I personally believe we go into the Barcelona game in better shape than last year. We had so many uncertainties last season – Robin [van Persie] was injured, William Gallas went off in the first game, Andrey Arshavin went off after 27 minutes, we had no Alex Song or Fábregas in the second game … The team, for me, had less confidence and we have matured since then. We can certainly compete technically better with them. It will be interesting to see whether we play with belief.

"You can wonder whether we need to change the way we play at the Nou Camp but, at home, we will try to play to our strengths. We will try to attack the other team. If we just play in the final third defensively, that would not be our natural game and we would not be happy – we'd come out of the match thinking we hadn't played. But if we can escape their pressure, then we can be dangerous. We will create chances if we can put them under pressure. We have to think about how we do that."

The size of the task awaiting Arsenal was put into perspective by Fábregas who acknowledged the Catalans are "the best team in the world" at present. "We have a young team but one with a lot of quality and energy," he said. "We are very motivated. They are such a good team that, even if you know everything [about them], they have so many quality players that they can make the difference. We don't have to worry too much about them. We have to play with no fear. Last season in the first half [of the first leg] especially we respected them too much. We just have to play our game and that is it."