Arsenal have the upper hand going into the second leg in Rome in a fortnight's time, as a Robin van Persie penalty defeated the Giallorossi at the Emirates Stadium.
Arsenal came into this game in big trouble domestically, as they were in real danger of failing to finish in the top four of the Premier League. The Gunners had a number of injury problems, as Tomas Rosicky, Theo Walcott, Eduardo da Silva, and Emmanuel Adebayor were all out, while Andrei Arshavin was suspended. Manager Arsene Wenger went for a bold 4-4-2, pairing Nicklas Bendtner and Robin van Persie in attack.
Roma also had a whole host of selection issues, particularly in defence as Juan failed to make the game, meaning that Simone Loria partnerred Philippe Mexes in the centre. Cicinho also wasn't passed fit, so Marco Motta played at right back. With doubts also over Alberto Aquilani and Mirko Vucinic, Simone Perrotta and Julio Baptista both started, with the Brazilian linking up in attack with captain Francesco Totti, who himself only just recovered in time for the game.
Arsenal had much the better start, and wasted a golden opportunity after six minutes, as Samir Nasri cut the ball back to Bendtner 12 yards out, but the forward miscrontrolled and the chance went begging. Nasri then headed wide from a left wing cross.
Emmanuel Eboue launched a lightning break on 13 minutes, and was cynically taken out by Mexes as the attack became really dangerous. The Frenchman was booked.
Arsenal's dominance in the early stages was overwhelming, and Alexander Doni had to race off his line to take the ball off van Persie.
However, with their first attack of the game, Roma almost took the lead, as Motta unleashed a rocket from 30 yards that was destined for the top corner, but Manuel Almunia performed a stunning finger-tip save around the post. Loria then missed a decent opportunity as he flicked the ball over from a left-wing free kick.
Having seen Motta try his luck, Nasri fancied his chances down the other end, as he fizzed a 30-yard effort not too far wide of the post. Abou Diaby fired well over from a similar position.
Roma started to tame Arsenal after their strong start, and Julio Baptista lashed wide with his left foot just shy of the half-hour mark. Rodrigo Taddei then cut back to Totti on the edge of the box, who lashed over.
Roma seemed to be coping well with the Arsenal attacks, but on 35 minutes they shot themselves in the foot, as Mexes tripped Van Persie in the box, and the referee pointed to the spot. The Dutchman stepped up himself and made no mistake, sending Doni the wrong way to put Arsenal ahead.
It could have been two moments later, as Van Persie skipped past Loria and cut-back for Bendtner, but Motta made a crucial recovery tackle.
Roma received a big blow just before half time, as De Rossi was booked for a lunging tackle, meaning that he will miss the second leg in two weeks time.
There was a curious start to the second half, as Arsenal began with nine players as Kolo Toure and William Gallas were late arriving from the changing rooms. Toure was booked for entering play without permission.
Arsenal had the first attempt as Van Persie fired wide from a narrow angle, but on 52 minutes Bendtner missed a glorious chance to double the home side's lead. The ball eventually found its way to the Dane at the back post, but with just Doni to beat, he fired over the bar.
Roma were giving the ball away for fun, and Bendtner laid the ball across the six-yard box, but it missed everyone, as the Italians survived.
Arsenal were completely dominant now, and Doni flew to his left to make a wonderful save from Diaby's 20-yard piledriver. Roma had to make a change, and they introduced David Pizarro for Brighi.
Arsenal continued to control the game, and they were guilty of another incredible miss on 66 minutes as Loria made a comical hash-up of a header, allowing Eboue a clean run on goal. However, the midfielder shot wide after dallying on the ball.
John Arne Riise almost made Eboue pay for his miss minutes later, as he fired a daisycutter inches wide of the far post.
Arsenal began to sat back in the closing 15 minutes, and they invited Roma to have more of the play. However, the Italians were struggling to break through, and indeed Arsenal substitute Aaron Ramsey forced Doni into action with a deflected shot on 85 minutes. Nasri also fizzed an effort wide moments later.
The closing minutes passed by without too much note, and there is all to play for in the second leg at the Stadio Olimpico in a fortnight's time.
Arsenal: Almunia; Sagna, Gallas, Toure, Clichy; Eboue (Ramsey 81), Denilson, Diaby (Song 61), Nasri; Bendtner (Vela 66), Van Persie.
Roma: Doni; Motta, Mexes, Loria (Diamoutene 70), Riise; De Rossi, Taddei, Brighi (Brighi 56), Perrotta; Baptista (Vucinic 82), Totti
Van Persie pen 35 (A)