Chelsea failed to shake off its recent blues with a 1-1 draw against bottom club Racing Genk in the Champions League on Tuesday, which nevertheless increased the English club's lead atop Group E.
A 26th-minute goal by Ramires after being set up by Fernando Torres gave Chelsea the lead, but Genk striker Jelle Vossen equalized when unmarked in the penalty box to score from an assist by Fabien Camus from close range in the 61st minute.
That left Chelsea ruing a missed first-half penalty from David Luiz, whose low shot was easily saved by Laszlo Koteles close to halftime.
A bad night was saved by Valencia, which beat Bayer Leverkusen 3-1 in Spain. It left Chelsea with two more points than second-place Leverkusen and three more than Leverkusen.
''It gets a little bit tighter,'' Chelsea coach Andre Villas-Boas said.
Villas-Boas kept John Terry on the bench throughout the game, only hours after police launched a formal investigation into whether the England and Chelsea captain racially abused Queens Park Rangers defender Anton Ferdinand in a Premier League match.
Facing reports Chelsea fans had targeted Ferdinand with chants during Tuesday's match, Villas-Boas said he heard nothing, adding ''I was concentrating'' on the match.
He did bring on England midfielder Frank Lampard in the 66th minute to look for victory against the group outsider, but after a 5-0 win over Genk at Stamford Bridge two weeks ago, scoring was tough going this time.
''We could not find the back of the net and that was the difference,'' the Portuguese manager said.
Lampard could have clinched the win in the 78th when he was unmarked in the goalmouth, but he inexplicably missed a tap-in and sent the ball wide.
In second-half injury time, Malouda chipped the ball toward goal, but South Africa defender Anele cleared it off the line in a melee.
Chelsea should never have been put in such a bind after it quickly gained control of the match at the sellout 22,000 Cristal Arena and dominated for most off the match.
But after two Premier League losses, including Saturday's 5-3 home defeat against Arsenal, things do not come easy.
''There is never a a negative momentum. There are difficult games to play and you have to play them to win,'' Villas-Boas said.
