Arsenal started life after Cesc Fabregas with a slender victory over Udinese in the Champions League qualifier first leg at Emirates Stadium.
Theo Walcott's early goal ultimately proved decisive - but Francesco Guidolin's Serie A side deserved at least a draw for their enterprise and will pose a real danger in the return in Italy next Wednesday.
Arsenal, with Fabregas finally reunited with Barcelona and stripped of injured Jack Wilshere, lacked their usual craft and the lively Gervinho was often forced to fight a lone battle up front with newly-appointed captain Robin van Persie suspended.
And Udinese almost took advantage of a disjointed display as they came close to scoring an away goal on several occasions, with veteran skipper Antonio di Natale a constant threat to the Gunners' defence.
Arsenal were fortunate when he hit the woodwork twice in the first half and brought an athletic stop from keeper Wojciech Szczesny, who also saved well from Pablo Armero in the first half, late on as Arsenal were forced to suffer to protect their narrow advantage.
Walcott almost added a second in injury time only to see his close-range shot brilliantly saved by Udinese keeper Samir Handanovic, but such a margin would have been cruel on the Italians.
Arsenal manager Arsene Wenger cut an agitated figure as he watched from the stands while serving a touchline ban, and Udinese's celebrations with their fans at the final whistle suggests they are confident of overcoming the deficit at home.
Arsenal's depleted side craved an early goal to lift the spirits with Fabregas gone and Samir Nasri heavily linked with a move to Manchester City and it arrived after four minutes when Walcott applied a perfect near-post finish to Aaron Ramsey's cross.
Udinese settled swiftly after and troubled an Arsenal defence that carried an air of vulnerability that was in sharp contrast to their inventive attacking play.
Di Natale, Serie A's top scorer for the past two seasons, curled a free-kick against the bar before Pablo Armero strode through Arsenal's defence with embarrassing ease on a 50-yard run that ended with Szczesny making a vital block.
Gervinho and Walcott, in front of watching England coach Fabio Capello, were prominent for Arsenal but Udinese grew in confidence and the dangerous Di Natale grazed the outside of the post as the Italians sensed growing anxiety in the Gunners' defence and the crowd.
Johan Djourou came on for Kieran Gibbs, who suffered a hamstring strain, at the interval but he only had time to put in a crucial tackle on Di Natale as he looked poised to equalise before he suffered a similar injury and was replaced by teenage summer signing Carl Jenkinson.
Udinese dominated possession, with Mauricio Isla shooting across the face of goal - but Walcott had a chance to extend Arsenal's advantage with 20 minutes left, only to finish tamely and off target.
The lively Di Natale had Szczesny stretching again to turn away another precise free-kick that was heading for the top corner with 16 minutes left before the final opportunity came and went for Walcott.
Arsenal's pleasure at the final whistle was tinged with relief after an anxious night that left Wenger simply grateful for the victory.