It was a pity that an FA Cup tie of this quality should have a referee's error at the heart of the outcome, and not just any error, but a mistake from Howard Webb that got no easier to explain on the third, fourth or fifth viewing.
With Liverpool chasing the tie on 65 minutes and Luis Suarez running into the left of the area, his legs were taken away by Alex Oxlade-Chamberlain with the ball far enough beyond both of them for there to be no question about it being involved.
In defence of Oxlade-Chamberlain, it was not sneaky or malicious or even particularly cynical – it was just a plain old dumb foul that screamed penalty. Asked about it later, the Arsenal man, who scored his side's first goal showed the politician's sleight of hand in avoiding the question of the legitimacy of whether it was a foul or not, pointing out that he only worried about the decisions that were given against him.
He had not tried to con the referee and one suspects that, had Webb pointed to the spot, there would have been a resigned trudge to the edge of the area rather than animated protest.
Webb had already given Liverpool one penalty, when Lukas Podolski clipped Suarez's leg. Steven Gerrard dispatched Lukasz Fabianski to one side of his goal with the power of a glance in that direction, slotted his penalty into the other and his team were back in the tie with enough time for another goal.
Whether it was Suarez's past reputation for simulation that crossed the World Cup referee's mind, as he made that split-second decision, is debatable.
More likely it was that he had given a penalty just seven minutes earlier that he may not have been completely convinced of and was in no frame of mind to do it again.
Liverpool manager Brendan Rodgers, to his credit, did not excoriate the referee after the game, but you could see he was unhappy when insisting that Suarez should be given legitimate penalties, regardless of his reputation.
A clue to Webb's thinking came later when Gerrard, already booked, fouled Oxlade-Chamberlain as he prepared to cross from the right wing and was not given a second yellow card.
Although the referee had also avoided booking Podolski on a number of occasions, one got the strong sense that Webb, having realised he had got the second penalty call wrong, was subconsciously opting out of big decisions from there on.
In so many aspects of the game Liverpool were the better side and, even after they had gone behind within 16 minutes, it felt like a matter of time before they would eventually punish Arsenal, but the goals never came. When it seemed they would overwhelm Arsenal, they began the second half by being carved open for Podolski's goal.
As for Arsenal, they rediscovered their confidence following the thumping at Anfield in the Premier League last weekend and the failure to beat Manchester United at home in midweek. Wenger made seven changes to his team, including a debut for Yaya Sanogo, which looked brave at the time. He later justified it by saying that many of his changes were a question of fitness. Jack Wilshere has a back problem, while Santi Cazorla and Kieran Gibbs, both second-half substitutes, were ill and not fully fit respectively. Bacary Sagna was "tired."
Sanogo played a role in the goal for Oxlade-Chamberlain, and despite a willing shift was raw at best. He was in the team in place of Olivier Giroud, who saw fit before the game to tweet his apologies about having been less than truthful over an extramarital relationship. Such are the demands made upon the modern footballer.
In his absence, there was a much better performance from Mesut Özil and Oxlade-Chamberlain.
The old defensive double act of Per Mertesacker and Laurent Koscielny, for the most part, did their job and, when he was called upon, Fabianski had a good game, especially two saves from Daniel Sturridge, the first of which was in the initial five minutes.
At the end of the game, Sturridge, who had missed three decent chances, looked like he was doing his best to express his sorrow with a prolonged bout of reflective sitting down on the pitch. Then he walked, hangdog, to the away fans to hand over his shirt as an act of penance. "He's a wonderful player," Rodgers said of Sturridge. "We can't hold it against him."
In an early blitz by Liverpool Gerrard picked out Sturridge with a through ball and Fabianski saved. Shortly afterwards, Suarez played in his strike partner and Sturridge went round Fabianski but hit the side-netting with his shot. Oxlade-Chamberlain scored on 16 minutes. Özil recycled a free-kick from Mikel Arteta, Gerrard blocked Sanogo's shot and the young Englishman followed up.
Towards the end of the half, Sterling grew stronger, accelerating around Carl Jenkinson at one point before stumbling over his cross. His response to Webb was a concern, with Gerrard called over to placate his team-mate.
Arsenal's second goal, after half-time, was excellent. Sterling lost the ball on the left and from Özil to Oxlade-Chamberlain it was worked to Podolski to finish.
Their confidence grew and after the hour Rodgers made a major tactical change, bringing off Aly Cissokho for Jordan Henderson, switching Jon Flanagan to left-back and moving Sterling to cover most of the right side.
He pushed his full-backs on and left the defending to his centre-halves.
It was an anxious finale for Arsenal, especially when Fabianski came for a cross and got nowhere near to it. Luckily for him, Daniel Agger's header was off target. In the end it came back to the penalty that had not been given at a time when Suarez was the key player for Liverpool. In Rodgers' view, his side had "virtually dominated most of the game".
That might be putting it a bit strongly, but they came in the mood to win the match and had the chances to do so.
But Arsenal held them off to earn a tie against Everton and the team-change gamble worked for Wenger, who retains an interest in a trophy that, whatever happens to Arsenal in the league, would make for a nice end to his season. (© Independent News Service)
City given chance for revenge against Wigan
Favourites Manchester City have an opportunity to avenge last year's final defeat to Wigan after Manuel Pellegrini's team were handed a home tie against the Championship side in the FA Cup quarter-finals.
Arsenal will again welcome Merseyside opposition in Everton, while there could be a Sheffield derby at Bramall Lane as United await the winners of the re-arranged tie between Wednesday and Charlton. Sunderland, with a League final to come, will be away to the winners of tonight's match between Brighton and Hull.
FA CUP quarter-final draw
Arsenal v Everton;
Brighton or Hull City v Sunderland;
Sheffield United v Sheffield Wednesday or Charlton Athletic;
Manchester City v Wigan Athletic.
*Ties to take place on March 8-9