Arsenal made a winning start to their Champions League campaign thanks to an own goal by PSV Eindhoven's Alex.
The Brazilian defender turned the ball into his own net after a brilliant surging run and cut-back by Arsenal striker Thierry Henry on 41 minutes.
Moments earlier, Robert Pires had had a header ruled out for offside.
Jan Vennegoor of Hesselink went closest to scoring an equaliser for PSV, but he blasted his shot wide of the goal and Arsene Wenger's men held on to win.
Arsenal, who have traditionally been slow starters in the Champions League, began their current campaign in similar fashion.
Despite dominating possession, the Gunners failed to hit their stride immediately and spent most of the opening period playing a game of patience with their opponents.
Jose Antonio Reyes, who replaced the injured Freddie Ljungberg in the starting line-up, showed flashes of his pace down the left.
But it was not until the home side collectively stepped up a gear that they threatened PSV's defence.
Patrick Vieira and Pires both wasted good opportunities when well-placed and should have at least tested the goalkeeper.
Pires had a header ruled out for offside after Edwin Zoetebier could only parry Henry's fierce shot across the face of goal.
The French winger reacted quickest, but a little too quickly for the assistant referee's liking, who deemed Pires had marginally strayed into an offside position.
But the increased intensity of Arsenal's attack finally paid dividends just before half-time.
Henry picked up the loose ball on the left of the PSV area and burst past the defence, cutting back his pass into the danger zone.
Vieira too had surged forward and his presence forced PSV defender Alex to turn into his own net.
After the interval, the Gunners failed to find their first-half intensity.
PSV's Park Ji-sung sent a powerful header over Jens Lehmann's crossbar to remind their Highbury hosts that the match was still in the balance.
PSV coach Guus Hiddink brought on Vennegoor of Hesselink in place of Gerald Sibon.
And the striker went closest to finding an equaliser for the visitors, blasting a shot across the face of goal which Pascal Cygan almost deflected past Lehmann.
Arsenal survived that scare and maintained their one-goal advantage to get their Champions League quest off to a jittery but winning start in Group E.
Arsenal: Lehmann, Lauren, Toure, Cygan, Cole, Pires, Vieira, Silva, Reyes (Edu 78), Bergkamp, Henry.
Subs Not Used: Almunia, Van Persie, Fabregas, Pennant, Clichy, Hoyte.
Goals: Alex 42 og.
PSV: Zoetebier, Ooijer, Alex, Bouma, Lee, Van Bommel, Cocu (De Jong 82), Vogel, Park, Sibon (Vennegoor of Hesselink 66), Beasley (Farfan 59).
Subs Not Used: Gomes, Lucius, Lamey, Feher.
Booked: Ooijer.
Att: 34,068.
Ref: Domenico Messina (Italy).