Manager Arsene Wenger is refusing to take anything for granted after Arsenal's 3-2 win at Celta Vigo in the Champions League first knockout round.
"The tie is far from over. Our mental approach will be vital in the second leg," Wenger said after Arsenal's first competitive win in Spain following five defeats and a draw.
"Celta Vigo made us work very hard tonight and we will have to be as determined in the second leg to make sure we go through."
The battling victory capped a momentous few days for the London club during which they moved seven points clear in the race for the English Premier league title and unveiled plans for a new stadium.
Arsenal were far sharper than Celta and but for two uncharacteristic lapses in defence, the English side would have won by a far greater margin.
"I think we will have to defend better in the second leg to go through," said Wenger. "I think they played well going forward but in the second half when we had more space we knew we could score more goals."
Only the likes of European Cup holders AC Milan or former champions Real Madrid, Juventus or Manchester United seem capable of beating Arsenal on their current form.
A treble of the English Premier league title, the FA Cup and the European Cup is a distinct possibility.
VERY SIGNIFICANT
"I think this victory showed how far we have come this season," said Arsenal skipper Patrick Vieira said.
"This is the type of game we might have lost or drawn a few years ago but the fact we won is very significant. They came back twice after we scored, but we were resolute and did well to come back and win the game."
Arsenal went ahead with a scrambled goal from Edu after 18 minutes before his namesake in the Celta side Luis Edu equalised with a well-taken header nine minutes later.
Arsenal's Edu struck again with a superb right-footed shot after 58 minutes only for the home side to equalise six minutes later with a scrambled goal from Jose Ignacio.
The game was settled 10 minutes from time when Thierry Henry combined with his French international team mate Robert Pires who finished a delightful exchange of passes with a fine goal.
Radomir Antic, the Celta manager, complained that Swedish referee Anders Frisk denied his side three penalty decisions.
Arsenal return to league action and their drive towards the English title on Saturday, seeking to extend their unbeaten start to the league season to 27 matches against Charlton Athletic. Celta continue their battle against relegation from La Liga with a visit to Real Madrid.
"We must show a lot of character to come back from this defeat," said Antic.