"I'd like to take the morale of the guys out of it, after twice fighting their way back into the game and being rewarded in the end," Keller said.
Schalke goalkeeper Timo Hildebrand and attacking midfielder Kevin-Prince Boateng are expected to return from a back injury and knee problems, respectively, but midfielder Marco Hoeger is out for the rest of the season with a cruciate ligament injury.
The German club has lost only two of its last 13 home matches in the Champions League, qualifying included.
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RECOVERY MISSION
Chelsea's record in Germany is poor, with four losses in six away games against Bundesliga sides, not including the Champions League final in 2012, when the club defeated Bayern on penalties in Munich to lift the title for the only time.
After Saturday's 4-1 win over Cardiff, attention has turned to qualifying from Group E.
"Having dropped three points against Basel at home we recovered at Bucharest and now is the moment we play two games against Schalke," Chelsea goalkeeper Petr Cech said after his 300th Premier League appearance. "We need to make sure we get the points to qualify. It will be a tough test but if we get six points out of those two games we will be in a good position in the group."
Chelsea's overall record against Bundesliga opponents is seven wins from 15 meetings, with four draws and four losses.
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FAMILIAR FACES
Chelsea forward Andre Schuerrle played for Bundesliga sides Mainz and Bayer Leverkusen, scoring in two victories over Schalke in eight games between 2009-13 before he made the switch to London in the offseason.
Schuerrle will be also be familiar with Schalke's Benedikt Hoewedes, Julian Draxler, Dennis Aogo and Roman Neustaedter from their time with the German national team.
"Of course it's nice to be going back to Germany. Against Schalke, in this stadium, with such fantastic fans. I'll be coming up against one of my best friends in football, Adam Szalai, too. It will be a special game for me," Schuerrle told the Bundesliga website. "Of course it means a lot to us as a team in sporting terms."
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GREENPEACE PROTEST
Group E became the focus of protest by environmental activists in Basel three weeks ago, and Tuesday could be set for more.
Greenpeace has targeted the Gazprom-sponsored Champions League to highlight Russian authorities' treatment of 30 activists and journalists who were detained when their ship was seized last month near an Arctic drilling platform operated by the oil and gas supplier.
UEFA fined FC Basel 30,000 euros ($41,000) last week for allowing four Greenpeace protesters to delay the match against Schalke several minutes by abseiling from the main stand roof to unfurl a banner. Home teams are responsible for stadium security.
Schalke vs. Chelsea brings together two teams that are also sponsored by Gazprom.
Schalke has the Russian firm as its shirt sponsor, and Chelsea signed a three-year commercial deal for Gazprom to provide its oil and gas and be its "Global Energy Partner."
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ON A ROLL
FC Basel heads to Bucharest with Swiss football on a high after the national team qualified for the World Cup as a seeded team.
Goalkeeper Yann Sommer, central defender Fabian Schaer and winger Valentin Stocker seem sure to be in the Switzerland squad in Brazil, and midfielder Fabian Frei is on the verge of selection.
Teammate Mohamed Salah looks unlikely to join them as Egypt lost 6-1 in Ghana in the first leg of their playoff last Tuesday.
Basel leads the Swiss standings by three points and enjoyed an easy 3-0 home win against St. Gallen on Saturday, watched by lifelong fan Roger Federer.
Several Steaua players have extra work ahead to reach the World Cup, as Romania is unseeded for the European playoffs.
Steaua is unbeaten in four home games against Swiss opponents but has yet to score in Group E and really needs a win to maintain any hope of emerging from it.
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AP Sports Writer Graham Dunbar in Geneva contributed to this report.