Salomon Kalou kept Chelsea's title aspirations alive with a second-half double to leave Middlesbrough entrenched in the relegation zone after a 2-0 defeat at Stamford Bridge.
Kalou opened the scoring in the 58th minute and added a second 10 minutes from time as Chelsea moved second in the table, two points behind leaders Manchester United.
Middlesbrough have now gone 11 games without a win in the Barclays Premier League and this latest setback will only increase the pressure on boss Gareth Southgate.
Chelsea's start was hardly inspiring, though, with a hopeful dribble into the penalty area from Salomon Kalou the highlight of the opening 10 minutes of the game.
The Ivorian striker bamboozled most of the Boro defence but ran out of space before he could test keeper Ross Turnbull.
Middlesbrough had clearly arrived at Stamford Bridge intent on earning at least a point by the way they had packed their midfield.
New loan signing Marlon King was left isolated as a lone striker with Boro sticking to a five-man midfield.
But Chelsea still found a way to bypass the crowded midfield and, in the 13th minute, it almost brought them the opening goal.
A right-wing cross from Jose Bosingwa found Ashley Cole unmarked at the far post but the England defender headed the ball into the side-netting.
In the 15th minute, Michael Ballack, two-goal hero of their win over Ipswich in the FA Cup on Saturday, almost put the Blues in front with a trademark free-kick.
Ballack's second goal against Ipswich was a delightful free-kick over Town's defensive wall, this time he cleverly curled the ball towards the corner only to see it skid on the wet surface and bounce off Turnbull's chest.
Frank Lampard, another free-kick hero against Ipswich, got the chance to repeat his feat in the 32nd minute but this time he sent his 25-yard effort over the crossbar.
Chelsea's continued reliance on trying to pass the ball through a nine-man defensive barrier was clearly not working.
Their best hope was to score from a set-piece and Kalou almost obliged in the 35th minute when he headed a corner from Lampard just too high.
Three minutes later Malouda and Kalou combined to set up a shooting opportunity for Lampard on the edge of the penalty area.
The England midfielder, invited to pick his spot by the static Boro defence, sent his effort just the wrong side of Turnbull's left-hand upright.
Chelsea boss Luiz Felipe Scolari and Middlesbrough assistant Malcolm Crosby were at odds with each other when Mohamed Shawky was penalised for handball.
Scolari lifted his hand to the referee to demonstrate he felt Shawky, already booked, should have been sent off.
The Brazilian's actions incensed Crosby and the fourth official had to intervene as the pair traded insults and gestures.
The banter between the pair continued right up and until the half-time whistle when Chelsea were jeered off.
Scolari was clearly not happy with the first-half performance and replaced Malouda with Didier Drogba at the interval.
They should have opened the scoring shortly after the re-start when a corner from Lampard reached the head of Ballack.
The German international cleverly knocked the ball back to Alex, whose header was goalbound until team-mate Kalou inexplicably got in the way and glanced it over the bar.
Moments later Chris Riggott was booked for a foul on Drogba and Alex's resultant 30-yard free-kick was deflected for another corner.
This time they broke the deadlock through Kalou in the 58th minute.
Middlesbrough defender David Wheater could only partially head clear and Kalou volleyed the ball into the roof of the net.
The Ivorian celebrated with a bizarre handcuff-style gesture with both wrists crossed in front of him.
Middlesbrough's response was to send on Afonso Alves and Tuncay Sanli in place of Shawky and King in the 63rd minute.
Chelsea could have added a second when Drogba and Nicolas Anelka combined superbly.
The Ivorian's clever pass set up Anelka perfectly but the France striker sent his shot into the arms of Turnbull at the near post.
Kalou made it two for Chelsea 10 minutes from time with his last act of the game.
The Ivorian rose unmarked to head home a corner from Lampard after Middlesbrough goalkeeper Turnbull had completely miss the ball.
Kalou, who again celebrated his goal with the handcuff gesture, was then substituted by Scolari.
Middlesbrough boss Gareth Southgate accused Luiz Felipe Scolari of attempting
to get one of his players sent off.
Chelsea coach Scolari appeared to wave an imaginary card at referee Lee Probert
after Mohamed Shawky, who had already been booked, was penalised for handball.
Scolari's gesture incensed Middlesbrough's assistant coach Malcolm Crosby and
the pair exchanged words just before half-time.
Southgate also revealed that Scolari had refused to shake hands at the end of
the game which Chelsea won 2-0 thanks to a brace of goals from Salomon Kalou.
The win lifted Chelsea into second place in the table and kept Middlesbrough
entrenched in the bottom three.
''There were words between my assistant and Phil Scolari,'' said Southgate.
''He seemed to want to get one of my players booked. He didn't shake hands at
the end. A strange reaction, but that's his prerogative.''
Middlesbrough tried hard to stifle Chelsea but two moments of poor defending
cost them dearly.
Both Chelsea's goals came from corners and Southgate added: ''We realised we
had to keep things tight. You can't open up against a team like Chelsea.
''You expect a moment of real class, to be carved open a few times, but that
didn't really happen. Our discipline was really good.
''A bit of quality from a set-piece from us might have been our best manner of
scoring, so it's a big let-down to lose to two set-pieces given the quality we
were up against.
''That's unforgivable because it comes down to people not doing their jobs at
the end of the day.
''We're not where we'd like to be. We've had a tough run. But I don't think
anyone in the country expected us to get anything tonight.
''We should have had a bonus point. But we know what we have to do. We have
stability. We have players who can get us out of the situation we're in. We have
to tighten up on the things that went wrong tonight.''
Chelsea's assistant coach Ray Wilkins insisted there was no problem with the
Middlesbrough bench over Scolari's action.
Wilkins confirmed that he did shake hands with Southgate but went on to say:
''It's a very emotional game, isn't it? Passions run high.
''They ran high on their bench. They did on ours. That's the way the game is
''It's played with great passion on the pitch and off it, whether it is with
supporters or managers. I shook hands. It was a nothing conversation.
''I didn't even see the incident, to be honest. If the referee felt he
(Scolari) needed to be sent to the stands, he would have done that.
''But he didn't do that. The referee obviously felt quite comfortable with the
situation, and Steve Bennett (fourth official) was on the side and he obviously
felt okay with the situation.''
Chelsea's victory makes Sunday's visit to third-placed Liverpool a massive game
for the Blues but Wilkins does not believe the Reds are beginning to implode
after their 1-1 draw with Wigan.
''It is a massive game on Sunday,'' agreed Wilkins. ''Over the past couple of
years, we've had some fantastic games with them.
''I'm sure this will be the same. I've got no to make on whether Liverpool are
cracking up. They won't be.
''They've got top class footballers. We just worry about ourselves. We go there
with a very positive attitude, as we do every match.''