Schalke 04 coach Jens Keller faces a make-or-break Champions League clash against Swiss champions FC Basel on Wednesday with a third-straight defeat set to end the 43-year-old's one-year reign.

Having been dumped out of the German Cup last week with a shock 3-1 home defeat to Hoffenheim, Saturday's 2-1 loss at Borussia Moenchengladbach left Schalke 17 points behind leaders Bayern Munich in the Bundesliga.

Now Swiss champions Basel and Schalke meet in Gelsenkirchen with Group E's second qualifying berth on the line.

Should Chelsea lose at Stamford Bridge against Steaua Bucharest, the winners in Gelsenkirchen will top the group.

Third-placed Schalke must beat Basel to reach the last 16 and failure to reach the Champions League's knock-out phase -- which means prize money worth 3.5 million euros (US4.8m) -- could be the final nail in Keller's coffin.

"It's the most important game of the season for us, not just because it means a lot of money for the club," Schalke's Germany midfielder Julian Draxler told magazine Kicker.

"And all of us players want to present ourselves well on the big stage.

"That's why Basel is a very, very important game."

Draxler admitted the players need to produce a convincing performance to help keep Keller in office as their recent showings have only heightened calls for his dismissal.

"We have a responsibility to put our foot on the gas and win," said the 20-year-old.

"Anything else is up to the club's management."

Schalke's decision makers -- general manager Horst Heldt and Clemens Toennies, head of the advisory board -- have strongly hinted the axe will fall for Keller should Schalke fail to beat Basel.

Potential successors have already been mentioned in the German media with ex-Werder Bremen coach Thomas Schaaf a possible contender to replace Keller, who took charge in December last year.

The ex-Stuttgart boss still has supporters in the Schalke squad.

"We need to have some tunnel vision, there can be no distractions," said goalkeeper Ralf Faehrmann.

"The coach gives us a plan and it's not his fault if we don't stick to it."

Having reached the knock-out phase of the Champions League for the first time two years ago, Basel are eager to repeat the feat and avenge their 1-0 defeat to Schalke in Switzerland at the start of October.

The Swiss champions are second in the group and have already shown impressive form on the road this season in Europe.

They pulled off a shock 2-1 win over Chelsea in London and are currently top of the Swiss Super League with just one defeat.