Toby Alderweireld and Jan Vertonghen have provided the central rock that this season's fine defensive record has been built on - a record that will now be tested by their friend and Belgium team-mate Romelu Lukaku at Everton on Sunday.

Both central defenders remain ever present at the half-way point of the Premier League with only 15 goals conceded in 19 games as we sit fourth. Indeed, four players - Jan, Toby, Hugo Lloris and Kyle Walker - have started 17 of the 19 games, keeping seven clean sheets.

With in-form Lukaku and the Toffees on the horizon, what better time to talk to Jan and Toby?

Tell us about Romelu Lukaku, a player you both know so well from Belgium...

Jan: "I think he’s in the best form of his life. He’s doing very well. He’s a great guy, we know each other well. I’m happy he’s doing well. There seems to be more focus on him and he's doing better because of that."

Toby: "He’s been in great form all season so it’s going to be a tough game, I know him very well, he’s very strong, very quick, everybody knows how he plays, he’s very clinical in front of goal so it’s going to be a tough game for us."

Below: Lukaku on the ball in our goalless draw at the Lane in August

What are his strengths?

Toby: "He’s strong, he’s quick, he’s clinical, he can shoot with left and right so there’s a lot of things he can do, it’s not only strength, he does a lot of things so he’s difficult to defend against."

Jan: "He loves scoring goals and he’ll do everything to score goals right until the last minute. If they are 3-0 up or 3-0 down, he will go for goal time and time again. We will have to be focused, all 11 of us, to stop him."

We're at the half-way stage of the season and you are both ever-present - how do you view the season so far?

Jan: "We’re all pleased. Okay, you always think ‘we could have done better here’ but we’re doing well and we’re happy, not just with where we are in the league, fourth now, but the way we've improved our game. We play attacking football, the way the fans want to see us play, the way the gaffer wants us to play and the way we want to play and that’s most important."

Toby: "It gives you confidence if you know everybody is playing well. Players are not dropping down to a three or four out of 10, it’s always a six, seven, eight - that’s important. Everybody is feeling confident, we're feeling mature at the back as well and in difficult away games we don’t concede a lot of goals. I think in all the games the maximum amount of goals we’ve conceded is two so even on a bad day or in a difficult game we don’t concede too many goals and that allows the attacking players to make a difference."

Jan: "After the loss against Newcastle you could think ‘not this time’ but the main thing was we were disappointed, but we all felt that defeat was a one-off incident. That’s a good feeling, because you feel you can go on to the next game and win again and that’s what we’ve done with three wins on the bounce. That’s the best feeling of the season."

Toby: "On a personal level, the guys made me feel so welcome when I came here, it helped with my performances on the pitch. It’s nice to play with some guys that I already knew but all the defenders are helping me, Hugo is having a fantastic season as well so everybody is helping each other. I think that’s the strength of this team, we are not individuals, we are really a team that helps each other and we don’t think about the statistic of me or him, one makes a mistake, the other one picks it up and it goes both ways so that’s very important."