Arsène Wenger cannot escape the critics – even at 30,000 feet. Arsenal's beleaguered manager had delivered the latest crisis bulletin at Luton airport, which took in the bad news on Samir Nasri and Jack Wilshere, and he might have envisaged some brief respite on the plane to northern Italy, where his team face Udinese in the second leg of the Champions League play-off.

The in-flight magazine's cover interview looked promising enough. Beaming back in designer pinstripes was Tony Adams, the former Arsenal captain and Wenger disciple, who is managing FC Gabala in Azerbaijan. Here is what Adams had to say.

"One of the gifts Arsène has got is that he's a lovely human being and I respect him a great deal. But I've got to get it real: coaching isn't his strong point. I love him dearly, he's a fantastic psychologist but he's not a great motivator. I'd just laugh at his attempts to gee us up – but I come from a different place, time and culture."

Everyone has an opinion on Wenger – it has always been the case – but the Frenchman detects greater levels of negativity than ever before. Many supporters cannot understand how he has overseen the well-advertised departures of Cesc Fábregas and Nasri but, as yet, failed to sign high-profile replacements. Juan Mata, the Spain midfielder that Wenger chased, has opted for Chelsea, saying that they represented a more realistic bet for honours. "He doesn't necessarily tell you the truth," Wenger said.

The manager's insistence that he has signed quality reinforcements for a squad that has also lost Gaël Clichy, Denílson, Emmanuel Eboué and Carlos Vela has failed to convince. Gervinho apart, Wenger's new boys are teenagers – Carl Jenkinson, Alex Oxlade-Chamberlain, Joel Campbell and Ryo Miyaichi. Some fans no longer want rich potential.

Injuries and suspensions have already bitten – Wilshere's absence with an ankle problem that needs rest to avoid a stress fracture is particularly worrying – and the squad looked thin, not to mention lacking in cutting edge and confidence, in the defeat at home to Liverpool on Saturday.

Wenger needs to generate momentum and he must do so in a finely balanced Champions League play-off against pacey and threatening Serie A opponents and in hot and clammy conditions. His team won 1-0 in the first leg yet they were indebted to the goalkeeper, Wojciech Szczesny, and the crossbar. The margin for error is zero. The Europa League is nobody's idea of a safety net.

"Wilshere's injury is not ideal for us on the day we sell Nasri," Wenger said, adding understatement to the mix. "Now is also not the ideal moment to sell Nasri but it is a moment."

Wenger feels pinned on to the back foot. At the beginning of the club's pre-season tour of east Asia he said Arsenal could no longer be considered a big club if they sold both Fábregas and Nasri this summer. Those words have been flung back at him although, to no little derision at his pre-match press conference here, he denied saying them.

Wenger did not give the impression that he was close to signing the established player or players that the supporters crave, although he said he would strengthen and, unsurprisingly, he talked up the personnel who remain at his disposal. They needed to harness the negative energy created by the absentees and disappointments and channel it into something positive.

"Sometimes the fact that you lose big players gets the team on the edge a little bit and forces each of them to give a bit more, fight a bit more together and that is, of course, what we will want to show against Udinese," Wenger said. "You are always concerned of the consequences that a transfer like Nasri's can have but it's not an excuse. If you are strong mentally, you can increase the solidarity."

Nasri has not left Arsenal with everybody's best wishes. After Wilshere sent him a good luck tweet and said he had learned greatly from him, Emmanuel Frimpong, who has no qualms about ruffling feathers, entered the discussion. "Pfffff come on Jack," he wrote.

Wenger may have smiled at that. He wants to look to the future and with players who consider only faith and togetherness. Arsenal will need the qualities against a Udinese team with goals in them. Behind Antonio Di Natale, Serie A's leading scorer for the past two seasons, is the menace of Mauricio Isla, Kwadwo Asamoah and Pablo Armero.

"If we score, it's not enough," Wenger said. "We also have to be solid defensively. The Champions League is just our life. We want to be at the top. We do not want to be anywhere else."