Celta Viga 2 Arsenal 3
Short of hearing that Manchester United and Chelsea have formally conceded the title, it is hard to see how the past 10 days could have been much better for Arsenal.
Having twice beaten Chelsea to stay on course for the Double and learned that the funding is in place for their new ground, Arsene Wenger's team took a significant step towards the quarter-final of the Champions League last night.
The two goals Arsenal conceded from set pieces suggested they will need to tighten up defensively to be considered serious challengers for this crown, and ought to ensure they take nothing for granted ahead of the return at Highbury.
But Wenger's players had enough going forward to compensate for their deficiencies and should now finish the job. With away goals counting double, Celta will need to score at least twice.
Arsenal on two occasions allowed leads to slip before Robert Pires scored a winner that slightly flattered them.
Edu had confirmed his growing value and confidence by getting the opener via a deflection and then scoring a brilliant individual second. Arsenal have now won four European games on the trot.
Arsenal have fared dreadfully in Spain under Arsene Wenger - this win followed five successive defeats.
"It's a good challenge to put our record in Spain right," the Frenchman said before kick-off.
Few of the visiting supporters had expected their team to slip up here in Galicia.
After all, Arsenal have been in fantastic form, finished the first group stage of this competition strongly and were taking on opponents who are struggling in La Liga. Celta Vigo lie 16th in Spain's top flight.
Arsenal had got off to an ideal start, taking the lead inside 20 minutes with a goal that Edu will claim but which went in off the defender Eduardo Berizzo. Celta's goalkeeper Pablo Cavallero ended with a badly bloodied nose after his face struck Edu's knee as he attempted to gather the ball.
A four-minute delay ensued as he received treatment. Then Celta set out to show that though he was bloodied, they were unbowed.
It was the game's other Edu, a Brazilian striker playing for Celta, who headed the equaliser. He beat Patrick Vieira to a header after the former Arsenal full-back Silvinho sent over a dangerous free-kick.
Celta had deserved to get back level. They had made a positive start, building mainly through Edu and their experienced Russian Alexander Mostovoi.
Their best openings often came down their right, with Gael Clichy not as convincing as usual in his role as stand-in for Ashley Cole.
Though Arsenal's defence dealt with most threats, Celta had conjured an opportunity shortly before they fell behind.
Jose Antonio Reyes, starting his first Champions League game, gave the ball away cheaply, the Spanish side broke quickly and it needed a good tackle by Sol Campbell to deny Savo Milosevic, the one-time Aston Villa striker.
Reyes was not alone in struggling to make an impact. Generally Arsenal were finding it difficult to make clear chances against a determined, hard-working Celta side.
Thierry Henry was operating on the periphery and neither of the wide players, Pires and Freddie Ljungberg, could make serious inroads.
That was in part a tribute to Celta's willingness to close down quickly all over the field. And although Celta were creating little, it was not for want of trying.
They showed they could pose danger when Mostovoi released Edu, who brought a good save from Jens Lehmann.
Lehmann must have sympathised with Caballero when his opposite number took a blow to the nose in trying to prevent Arsenal from scoring. The ball was loose after Edu's header from Pires's free-kick struck a defender, but Edu reacted quickest and poked an effort that would not have gone in but for a deflection off Berizzo.
Inside the opening minute of the second half Arsenal were fortunate not to see that early lead turn into a deficit.
Edu's cross found Mostovoi unmarked and the Russian sent in a header that beat Lehmann but struck the bar.
A Jose Ignacio shot shortly after was further evidence of Celta's threat. Yet Arsenal, too, were showing greater verve in their attacking, with Reyes livelier, and soon began to exude menace.
Henry ought to have scored after Cavallero parried a Reyes shot, and three minutes later came a breakthrough.
Edu showed magnificent individual skill to beat three Celta players before curling a shot into the top corner with his weaker right foot.
He deserved better than Arsenal's poor defending at a corner less than 10 minutes later that allowed Jose Ignacio to score after Sergio Fernandez had won the header. But Arsenal produced another fine response, Henry and Pires combining for Pires to score.
CELTA VIGO: Cavallero, Velasco, Sergio, Berizzo, Silvinho, Luccin, Jose Ignacio, Angel (Vagner 64), Mostovoi, Edu (Pinilla 75), Milosevic.Subs not used: Pinto, Caceres, Contreras, Mendez, Jandro. Booked: Silvinho. Goals: Edu 27, Jose Ignacio 64.
ARSENAL: Lehmann, Lauren, Toure, Campbell, Clichy (Bentley 89), Ljungberg (Cygan 90), Vieira, Edu, Pires, Henry, Reyes (Kanu 78). Subs not used: Stack, Keown, Hoyte, Fabregas Soler. Booked: Edu, Henry. Goals: Edu 18, 58, Pires 80.
Referee: Anders Frisk (Sweden).