Schalke 04 coach Jens Keller faces a make-or-break Champion League clash against Swiss champions FC Basel on Wednesday with a third-straight defeat likely to cost the 43-year-old his job.

Having been dumped out of the German Cup last Tuesday by a shock 3-1 home defeat to Hoffenheim, on Saturday Schalke lost 2-1 at fourth-placed Borussia Moenchengladbach, who opened a seven-point gap over fifth-placed Schalke in the Bundesliga.

With the Royal Blues now 17 points behind Bundesliga leaders Bayern Munich and out of the German Cup, a Champions League exit -- albeit with entry to the Europa League if they finish third in Group E -- would end their interest in all three major competitions.

And it could well be Keller's last game in charge having taken over in December last year.

"You need to ask those in charge who make those decisions," Keller replied tersely when asked about his future after Wednesday' match at Gelsenkirchen's Veltins Arena.

"Yes," said Schalke's general manager Horst Heldt when aked if Keller would be in charge for Wednesday's match, but he refused to comment when asked about next Sunday's home Bundeliga game against Freiburg.

Clemens Toennies, head of Schalke's advisory board, said it is all about results now.

"Now is not the time to address the question about the coach," Toennies told magazine Sport Bild.

"It's all about winning our next few games."

Schalke are a side badly in need of a confidence boost after suffering their eighth defeat of the season in all competitions at 'Gladbach.

The Royal Blues can justifiably argue they were the victims of some harsh decisions by referee Felix Zwayer at Moenchengladbach.

With the scores level at 1-1, Schalke captain Benedikt Hoewedes was sent off for a second yellow card after a shot on goal ricocheted off his upper arm, earning the Germany defender a red card following an earlier yellow.

To make matters worse, striker Max Kruse converted the resulting penalty, on the stroke of half-time, which proved to be Moenchengladbach's winner.

"That was not a penalty, I was turning myself out of the way (of the ball) and it's a pity the game was decided by a goal like that," said Hoewedes.

Gladbach coach Lucien Favre agreed with the Schalke defender.

"The red-yellow against Hoewedes was, from my perspective, too harsh. Perhaps it's the rules, but it wasn't necessary," said the Swiss coach.

Only a superb save from Borussia goalkeeper Marc-Andre ter Stegen, deep in extra-time, from a Kevin-Prince Boateng header denied Schalke an equaliser as their luck deserted them.

Hoewedes admitted Wednesday's game is "all-or-nothing" now with regards to their season.