Johan Djourou has warned Roma that Nicklas Bendtner could be their worst nightmare in tomorrow night's Champions League showdown.

Arsenal travel to the Olympic Stadium defending a 1-0 lead from the first leg at Emirates Stadium a fortnight ago and with Emmanuel Adebayor out due to a hamstring problem, Bendtner is likely to partner Robin van Persie in attack as the Gunners look to reach their third quarter-final in four years.

With such a slender lead to defend, the Danish striker has arguably never started a bigger game in his career but after scoring 10 goals in something of a breakthrough season, Djourou insists his team-mate is close to becoming a major force on the big stage.

He said: "Nick is a really big mate of mine but he's also a great player who has everything. He's tall, he's quick, he's comfortable on the ball and that's a nightmare for defenders, the kind of player you don't want to be facing.

"He needs to believe in himself a little bit more but he is starting to do that now and he knows he has the quality. I think he's going to be unstoppable when he realises how much talent he has."

Djourou was expected to accompany Bendtner in the squad that travelled to Rome today after replacing Kolo Toure for Sunday's 3-0 FA Cup fifth round victory over Burnley.

The Swiss centre-half could again partner William Gallas at the heart of Arsenal's defence as Toure is still struggling with a calf problem picked up against West Brom last Wednesday.

The Gunners dominated the first leg against last season's Serie A runners-up and were somewhat unfortunate not to be taking more than an unanswered goal to the Olympic Stadium. But Djourou has vowed they will not sit back and defend despite the precarious aggregate scoreline.

He said: "It's a big game and we are in a good position because we won the first leg, although we could maybe have been in an even better position.

"It's going to be a difficult game but it's a trophy we are looking to win. We're going to have to give everything to get that result because we can't go there just to defend and worry about not conceding. Roma are going to come out and try and win the game."

Luciano Spalletti's side are hopeful of having strike duo Francesco Totti and Mirko Vucinic available after injury.

Roma captain Totti, who looked unfit for the first leg at Emirates Stadium, was not risked in Saturday's 1-1 draw with Udinese because of a knee problem but is expected to take part in light training today. Striker Vucinic, who scored twice against Chelsea in the group stages, is struggling with a back problem but is winning his race to be fit, with a place on the bench now considered a last resort.