Arsenal 1 Udinese 0

Arsenal have their noses ahead in Europe but they know that they face a tough task in northern Italy next week if they are to reach the Champions League group stages for the 14th season in succession.

Theo Walcott’s fourth-minute goal gave the Gunners a slender lead which they hung on to, precariously at times, to take to the Stadio Friuli next Wednesday.

On the evidence of tonight, Udinese will provide a stern test of Arsenal’s defensive credentials next week, and it was only due to some excellent saves from Wojciech Szczesny that Arsenal maintained their lead to the midway point in the tie.

To add to his woes in what has been an immensely difficult month so far for Wenger, both Kieran Gibbs and his replacement, Johan Djourou, limped off with injuries. With Gervinho and Alex Song suspended for this weekend’s game against Liverpool, and numerous others on the treatment table. Arsenal may struggle to put out any kind of decent side on Saturday.

Againt the Italians, Wenger largely stuck with the side that had earned a point at Newcastle on Saturday, although Marouane Chamakh came in for suspended Robin van Persie and Wenger decided to give Walcott a start ahead of Andrey Arshavin after the latter’s anaemic display at St James’ Park.

The Gunners had left Newcastle knowing that many of their supporters were far from happy with the way the summer had gone in the transfer market, and with Cesc Fabregas having left since then, the atmosphere at the Emirates was one of both expectation and distrust.

Before most of those disgruntled supporters could take their seats, however, Arsenal were ahead. From almost their first attack, Aaron Ramsey surged clear down the right flank and crossed to the near post, where Walcott was waiting to prod a left-footed volley past Samir Handanovic.

It was the perfect start. Nerves were settled and the supporters calmed, but Udinese gradually began to show how they had finished fourth in Serie A last season with some artful attacking play.

Midway through the first half the Italians should perhaps have been level. Pablo Armero ran on to a loose ball in the centre circle and surged through a gaping hole in the Arsenal rearguard to force a fine save from Wojciech Szczesny. From the rebound, only a heroic block from Alex Song kept Arsenal’s lead intact.

At the other end, Arsenal failed to create any more clear-cut chances before the break, although Gervinho was testing the visitors’ defence, and Ramsey was looking comfortable in midfield, where Tomas Rosicky had once again been given a central role in the absence of the departed Fabregas, and the absent Samir Nasri, Jack Wilshere and Abou Diaby.

Arsenal went in at the break looking fairly comfortable, but re-emerged from the tunnel minus left-back Gibbs who had picked up a knock in the first half.

Djourou replaced him, with captain for the night Thomas Vermaelen moving to left back. But within 10 minutes Djourou was clearly struggling and had obviously tweaked something, and was duly replaced himself before the hour-mark with Carl Jenkinson.

The teenager who had spent part of last season on loan from Charlton to Eastbourne Borough in the Conference National was suddenly thrust into a Champions League debut, and Arsenal were coming under more pressure.

Szczesny was glad to see one drive from Kwadwo Asamoah fly just over his crossbar, and the Italians were enjoying plenty of possession before Walcott had a golden chance to double Arsenal’s lead on 70 minutes.

This time, however, the Englishman had much longer to think about his finish than his instinctive opening goal, and he failed with a laughable attempt to curl the ball around Handanovic. How Arsenal could have used a second goal to release the building pressure.

Wenger sensed it and made his final substation, another teenager entering the fray as Emmanuel Frimpong replaced the tiring Rosicky.

With quarter of an hour to go, Udinese’s celebrated captain and last season’s top scorer in Serie A, Antonio Di Natale, again brought his side tantalisingly close to an equaliser, curling a 25-yard free-kick over the Arsenal wall only to be denied by a fine save from Szczesny.

Walcott had one last chance to double the lead in the final moments when set up by a mazy run from Gervinho, but was denied by a superb save from Handanovic. In injury time, Armero fired just wide for Udinese.

This tie is still wide open and Arsenal know it. They will need to be at their very best to progress to the main draw next week.

Arsenal; Szczesny, Sagna, Vermaelen, Koscielny, Gibbs (Djourou, 45, Jenkinson, 59), Song, Ramsey, Rosicky (Frimpong, 71), Gervinho, Walcott, Chamakh. Subs not used: Fabianski, Oxlade-Chamberlain, Arshavin, Bendtner.