On the eve of facing Hamburg in a must-win game in the Europa League in Glasgow tonight, Tony Mowbray, the Celtic manager, had to defend himself yet again yesterday in the face of growing criticism about the rate of progress he is making at the club.

Following a 0-0 draw at home to Motherwell on Saturday, Celtic under Mowbray have won just two of their seven home matches so far this season, with three of those being in Europe. Celtic lost to both Dynamo Moscow and Arsenal in the Champions League qualifiers, and have taken their fitful form into group C of the Europa League.

Mowbray’s side, who have already lost 2-1 away to Hapoel Tel Aviv and drawn 1-1 with Rapid Vienna at home, almost certainly have to defeat an injury-ravaged Hamburg in Glasgow to keep their tournament hopes alive. Yesterday, however, it was his team’s shaky form which the Celtic manager was yet again having to defend.

Mowbray, in fact, disputed the suggestion of a teething Celtic team under his watch. “It’s an argument that can leave you vulnerable at times, but I’ve always been a performance coach — and I’m comfortable with the progress that we’re making,” he said.

“The performance against Motherwell on Saturday was there for all to see — I thought it was good, even though we didn’t win. But you get judged by people, probably without the professional eye, on results. I have to accept that.”

With his two biggest signings to date, Marc-Antoine Fortuné and Danny Fox, both out through injury, Mowbray has been further denied the chance to create a new Celtic in his own image. But he insisted yet again that only time would tell whether he can make a success of the job he has taken on in Glasgow.

“Hopefully, the vast majority of Celtic supporters understand the journey that we’re on,” Mowbray said. “This team will change as time moves on. It’s my responsibility to do that. With every window of opportunity you try to improve your team. As time goes on you do the best you can. A new manager surely he has a right to build a new team.

“You can only move people in the transfer windows, so when those windows open you try to improve on the quality you have. Nobody is saying here that [a specific player] will leave, but in time competition [for places] will be created, and people will fall by the wayside. That happens at every club. As the next window comes and signings arrive, you’ll see competition.

“I keep saying it, when I was at West Brom I think only two players remained from the 35 that I inherited. So there was a big change around. I believe West Brom were stronger when I left than when I arrived, and I think Celtic will be stronger the day I leave than from the day I arrived. But that has yet to be proven.”

Mowbray, under enough pressure as it is, is plainly wary of the threat posed by Hamburg, currently second-top of the Bundesliga. The German club has recently had four-times the budget that Mowbray has had to spend on players, and tonight may be a night for the Celtic to manager to sacrifice his belief in open, expansive football.

“Hamburg are a team who are above Wolfsburg — a team Manchester United had a real tough night against the other week,” Mowbray said. “They’ve got some good players and are a good team.

“We will go out to try to win, but understanding that they’ve got some very high-class players. Their third-choice centre-forward [Marcus Berg] cost £12 million, and they’ve got a left winger [Eljero Elia] who cost them £8 million. So let’s respect their talent.

“If we play an open game of football their talent will probably leave our players a bit exposed. So we have to ask the fans to be a bit patient at times as we are playing against a very good side.”