Jose Mourinho shouldered the responsibility for Chelsea's surprise 1-1 Champions League draw away to Maribor on Wednesday.

Just a fortnight after thrashing the Slovenians 6-0 at Stamford Bridge, Chelsea were kept waiting for their place in the last 16 of Europe's elite club tournament.

Indeed, the English Premier League leaders had to come from behind just to earn a point in this Group G clash after Agim Ibrahimi's superb curling shot had given Maribor a 50th-minute lead.

The hosts should have gone 2-0 up but Luka Zahovic somehow contrived to miss an open goal as the game entered its final 20 minutes and were made to pay when Nemanja Matic equalised.

Chelsea then missed several chances before Eden Hazard won a penalty with five minutes remaining after being brought down in the box by Mitja Viler.

Hazard took the penalty himself but impressive goalkeeper Jasmin Handanovic dived to his left to save the spot-kick.

Chelsea manager Mourinho, whose side are unbeaten in all competitions this season, had labelled the Blues' 6-0 win in west London a "fake situation" and told his players they'd face a sterner test in the return fixture.

"I was conscious of it, but I was not successful in passing over that message," the Portuguese boss said after Wednesday's match.

"If I cannot convince the players that the game is difficult and you have to play from minute one, obviously it's my responsibility."

Now Mourinho's men must win in Gelsenkirchen against a Schalke side managed by Roberto di Matteo -- who guided Chelsea to their 2012 Champions League triumph -- if they are to reach the last 16 with a match to spare.

Mourinho, twice a Champions League-winning manager with Porto in 2004 and Inter Milan in 2010, was far from happy with Chelsea's start on Wednesday.

"The first half we were not good. Very slow, no intensity, no creativity," he said.

"In the second half we played very well, but they scored.

"After that I thought we played magnificently: creative, fast, good dynamic, lots of chances to score.

"But I think it's fair to praise Maribor's efforts because they gave everything. They fought with everything to try to get the point."

Maribor coach Ante Simundza said he was proud of his team's performance in front of a passionate home crowd.

"We showed our character," he said. "With some luck we could have won, with some bad luck we could lose.

"The biggest difference compared to the match we lost in London 6-0 was that Chelsea then hit from every chance, this time with he help of our home crowd it was different."

Kurt Zouma could have given the visitors the lead but headed wide from a Cesc Fabregas corner.

But Chelsea failed to get going in the first half and Mourinho responded by sending on Costa and Oscar after the break in place of Willian and Schurrle.

However, five minutes into the second period the visitors were behind after Chelsea, failing to clear the ball properly, saw Ibraimi beat Petr Cech with a superb curling shot into the far corner.

Ramires replaced Filipe Luis as Mourinho switched to three at the back.

But as Chelsea were adjusting to their new defensive formation, Viler sped forward and crossed to the back post, where Zahovic shot over the top when it seemed easier to score.

Oscar's deflected shot led to Chelsea's equaliser from the ensuing Fabregas corner, with John Terry heading the ball down for Matic to lash home.

Hazard should have made it 2-1 but was denied by Handanovic when one-on-one with the goalkeeper, who later tipped Costa's volley over the crossbar.