A scrappy goal from William Gallas and a late Emmanuel Adebayor tap-in put Arsenal in control of their Champions League qualifier with FC Twente.
Arsenal were second best for much of a poor game in the Netherlands and both Marko Arnautovic and Romano Denneboom had chances to put FC Twente ahead.
But Arsenal got a break when Robin van Persie's free-kick deceived the home defence and Gallas bundled home.
Theo Walcott squared for Adebayor to put them firmly in control of the tie.
The two goals and a clean sheet should be enough to see Arsene Wenger's men through their second leg at the Emirates in a couple of weeks and into the lucrative group stages of the competition.
But the performance will have been more worrying for Wenger with the Premier League campaign just three days away.
The Gunners were a far cry from the side that was so pleasing on the eye last season as their passes frequently failed to locate team-mates.
606: DEBATE
Worryingly the backline looked suspect as ex-England boss Steve McClaren had his FC Twente side fired up.
Eljero Elia and Denneboom caused plenty of problems for a reshaped defence in the absence of Kolo Toure.
Denneboom headed over the bar in the opening minutes and then went even closer with a rising shot just off target after busting into the box unchallenged.
The Dutchman slipped a delightfully-timed pass through to Arnautovic to send him clean through, but a poor first touch allowed Manuel Almunia to come out and block his effort.
Ramsey showed the confidence of youth with a shot from way outside the box that failed to trouble Sander Boschker.
The Dutch side's keeper was beaten to the ball in a rare sight on goal for Van Persie, but the Arsenal forward could only knock a square ball into a danger area devoid of team-mates.
There was more urgency from Arsenal after the break but Gallas's goal still came as a surprise, not least to the defender as Van Persie's inswinger landed at his feet a few yards out.
Gallas managed to deflect the ball on target and Boschker could not react quickly enough to keep it out.
Arnautovic gave Arsenal another fright but the young striker, who has yet to break his duck for the first-team, poked into the side-netting.
With both sides tiring, Walcott's pace allowed him to get on the end of a hopeful through ball and he squared for an unmarked Adebayor, whose effort just squeezed under the body of Boschker.
It was anything but a textbook Arsenal victory, but for once Wenger will be happy to have won ugly.
FC Twente manager Steve McClaren:
"I think we should have scored in the first half. You don't get many chances and you have to take them. We didn't do that. We lost concentration on two occasions and got punished.
"That's what happens in Europe against the top teams. The inexperience in the dressing room showed and we have to learn from it.
"But I can't fault the performance. We had Arsenal rattled, especially in the first half."
Arsenal manager Arsene Wenger:
"We expected a very physical game and we were not disappointed.
"We needed to be patient and not make mistakes at the back.
"They dropped their level but to do what they did in the first half is very difficult and from then on we looked more comfortable.
"We were so young in the middle of the park for a game of that level and you could be worried but I have confidence in them."
FC Twente: Boschker, Wielaert, Tiote, Franco, Braafheid, Wilkshire, Brama, Arnautovic (Gerritsen 90), Janssen (Heubach 90), Elia (Huysegems 86), Denneboom.
Subs Not Used: Paauwe, Zomer, Wellenberg, Chery.
Booked: Janssen.
Arsenal: Almunia, Sagna, Djourou, Gallas, Clichy, Eboue, Ramsey, Denilson, Walcott (Randall 84), Adebayor, Van Persie (Bendtner 88).
Subs Not Used: Fabianski, Vela, Wilshere, Hoyte, Gibbs.
Booked: Denilson, Van Persie.
Goals: Gallas 63, Adebayor 82.
Att: 20,000.
Ref: Alberto Undiano Mallenco (Spain).
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