Following two of the most memorable nights in European football history, there may have been a slight sense of trepidation going into the second leg of Arsenal's Europa League quarter final tie against CSKA Moscow on Thursday night.

The Gunners were sitting pretty at 4-1 on aggregate, so it looked like a semi-final position was all but secured and the trip to Moscow was just a formality.

But just two nights earlier, Barcelona had made the trip to Rome for their own quarter final against AS Roma, and it too looked like a formality. But after 90 extraordinary minutes, the Catalan side were no longer involved in the Champions League after a humiliation at the hands of the Romans.

Arsene Wenger will have wanted to avoid this situation at all costs, but with 50 minutes on the clock at the VEB Arena, it seemed a near certainty that it was going to be the case. The Gunners were being dismantled by Viktor Goncharenko's side, and found them 2 goals down following a late first half Fedor Chalev strike and Kirill Nababkin strike to make it 2-0 to the home side.

Due to Aleksandr Golovin's exquisite free-kick in the first leg, if Arsenal somehow managed to lose the game 3-0, they would lose the match 4-4 on aggregate due to the away goals rule - a humiliating disaster that one would believe may be to harsh for even Wenger to come out of with his role as manager intact.

Thankfully for the Gunners - and generally against the run of play - Danny Welbeck managed to divert the blushes of his employers by netting past Igor Akinfeev following a nice passage of passing play. At 2-1, and 5-3 on aggregate, with only a quarter of an hour remaining, the game was effectively put to bed, but it was an enormous hassle to get that far in the end.

In injury time, Aaron Ramsey, who had been exceptional in the first leg, came up with a goal to put a gloss on the result. On paper, 2-2 away in Moscow is not an overly poor result, but the first hour of the game left a great deal to be desired.

The roughly 300 supporters who made the trip to Moscow were subjected to a very drab opening half hour, with neither team producing much. This, however, suited Arsenal as the impetus was very much so on CSKA to come out fighting, which relatively speaking, they failed to do.... until Chalov managed to bundle the ball into the away sides net following some calamitous defending from close range.

Going in at 1 goal down at half time no doubt changed the Arsenal mentality. It was 4-2 on aggregate, but after seeing what had happened in the other matches during the week, there was a sense that anything could happen and the side needed to be prepared for anything.

It didn't take long in the second half for the Moscow side to stake a genuine claim for progression when Nababkin stabbed in from near the goal following some good play by Golovin.

Golovin - who at just 21 years old looks like a fantastic player who will be high on the radar of teams across Europe in the Summer - came close to putting his side 3 goals to the good soon after through a free kick, with Petr Cech managing to just turn the ball by a post.

With over an hour gone, Wenger changed Jack Wilshire for Calum Chambers; a change brought upon by the midfielder picking up a slight ankle knock, but also to increase the amount of bodies at the back.

It was a moment of inspiration from an in-form Welbeck that proved to be the vital goal. The English forward has now scored five goals in his past five appearances - his name being seen more frequently on the score sheet will do his ambitions of making the English World Cup squad no harm.

It was Mohamed Elneny who fed the ball to Welbeck, and in injury time, following a more relaxed final 15 minutes, he turned provider once more when he found Ramsey, who made no mistake in the 92nd minute. On aggregate, the tie ended 6-3; a deceptively large scoreline gap in what was a tough tie.

At noon, Arsenal got the semi-final draw they feared - Atletico Madrid. The first leg is to take place at the Emirates, with a tough fixture at the Calderon to be the decider in who is making the final. It's an undoubtedly difficult fixture against a world class side, but to shine a positive light on the tie, one feels Arsenal would have to play Madrid at some point if they intended on winning the competition, so may as well get it out of the way. Also, Diego Simeone's side are beatable - that was proved last night when Sporting Lisbon won 1-0; only missing out on a semi-final place of their own due to Madrid's 2-0 home win in the first leg.

The other semi-final is going to be taking place between Red Bull Salzburg - who pulled off a spectacular win against Lazio last night - and Marseille, who came from behind to defeat Red Bull Leipzig. Both sides looked the least likely to qualify from their respective quarter finals, but they showed resilience and progressed.

Next up for Wenger's side is an away tie at Newcastle United in the more familiar territory of the Premier League. With two legs of a semi-final to worry about, the league will very much be occupying the bottom of Arsenal's priority list. In the Europa League, AC Milan and CSKA Moscow are both sides with European pedigree that Arsenal have managed to claim scalps from, but Atletico Madrid will likely provide the largest test yet.