Tony Mowbray warned the Celtic players they have until January to save their Parkhead careers after their Europa League hopes suffered an almost fatal blow with their 1-0 defeat by Hamburg.

The Hoops matched the visitors in the first half but failed to convert several decent chances and, in the 63rd minute, Swedish striker Marcus Berg claimed the points when he took a Ze Roberto pass before drilling his shot from distance past Artur Boruc.

Celtic remain bottom of the section with one point from three games ahead of the return game in Germany at the beginning of next month.

With no wins in his last four games, and only two wins in eight home games since taking over from Gordon Strachan in the summer, Mowbray again left the pitch to the sound of boos from the home fans.

However, the former West Brom boss believes the obvious lack of quality is costing him and he aims to do something about it when the transfer window opens again.

"It is down to the players to prove that they are good enough to stay at this club and play for these supporters, come January," the Parkhead boss said.

"We give them 10 out of 10 for effort but I have never questioned their effort.

"I can question their quality, as I did last Saturday against Motherwell and as I do again now.

"I saw our quality and I saw their quality.

"Manchester United win games because Rooney smashes it in and Berbatov creates space, Liverpool are finding it hard without Torres and Gerrard.

"The best players win you football matches, quality is what counts.

"Celtic fans should be happy with endeavour, effort and desire but they will see the miscontrolled passes, as I see them.

"We will try and put it together bit by bit.

"We will try to find the right players of the right quality to lift the team and we are working hard behind the scenes to find those players.

"The players are honest, hard-working players and they are very harsh on themselves.

"Players will get opportunities to remain at the club but the quality needs to improve and I have to work hard to do that.

"Nobody in this city seems interested in performance levels, it's all about results and we have to live with that and the result went against us.

"We probably need to win our last three games, so let's give it a go."