The leaders' recorded the club's biggest win at Middlesbrough as the perfect away run in the league continues.

It was a scintillating burst of team-attacking play in the second half that built on a 1-0 half-time lead. That had been thanks to a Kalou goal and the Ivorian would go on to score again among another Belletti long-range special and goals from Lampard and Malouda.

That Chelsea were suffering an 'injury crisis' now looks laughable with the result coming on the back of the excellent home victory over Aston Villa although by kick off, the medical picture had brightened considerable from how it appeared midweek.

Bosingwa, Alex, Terry and Anelka were all okay to start this lunchtime game and Deco was on the bench.

Interestingly, Scolari did not move Mikel forward to complete the attacking midfield four, instead opting for Belletti in a new role alongside Lampard with the Nigerian retaining the anchor spot.

Boro boss Gareth Southgate decided to counter Chelsea with Mido as the main striker supported behind by the pacy Aliadiere, denying Afonso Alves an initial chance to inflict pain of his fellow Brazilians in the Chelsea set-up

The Chelsea defence was briefly stretched three minutes after kick-off when Johnson on the Boro right found a way round the outside of Bridge but misdirected his ball across. Chelsea broke swiftly through Bosingwa and Kalou but the ball was blocked as Anelka was balancing himself to shoot.

Those moments apart, it was a quiet start inside a quiet Riverside Stadium.

Chelsea did our best to get the early afternoon going by scoring.

Belletti was involved in the action twice, first spinning a ball out to Bridge and then shooting when the left-back's cross was only half-cleared beyond the far post.

There was a touch of good fortune when the ball ricocheted twice off red-shirted players but Kalou didn't care as he turned the ball in from just six yards out. There were 13 minutes on the clock.

Too many Middlesbrough passes were going astray for the home fans' liking. Chelsea were very much in the ascendant.

Lampard was a couple of yards away from making it 2-0 on 23 minutes but he diverted Malouda's low ball into the six-yard box beyond the far post.

Gary O'Neil became the game's first booking for a lunge in at Alex as they went for a 50-50 ball.

Malouda hooked a shot well wide after another rapid counter-attack following Boro's first corner of the game with half-an-hour gone. He went closer with another effort eight minutes later after a third Chelsea corner.

The Blues contrived to give Middlesbrough a brief moment of hope in stoppage time at the end of the half but a stretching Terry and Cudicini restored calm. The game had not been overflowing with chances at the other end but the 1-0 score at the break still flattered Southgate's team as jeers greeted the half-time whistle.

O'Neil had the first shot after the restart, blasting a couple of yards over the Chelsea bar from distance but then we once again switched the game to the other end with devastating simplicity.

Suddenly Malouda was racing into the box with Anelka inside him but delaying the pass or shot, he allowed Grounds to catch him and the ball went away for a corner.

Would Chelsea be made to pay for failing to extend the lead? Not a chance as two goals in two minutes were turned past Turnball in front of the joyous Chelsea support.

First Belletti, who had not looked at all out of place when pushing forward, collected a Malouda pass in far-too-much space for Boro's safety. The shot from 30 yards couldn't have been more perfect, curling away from the keeper's reach and into the top corner.

Malouda was again involved in the third, a long pass by Bridge to the Frenchman out on the right squared inside to Kalou who struck the target via a deflection off Wheater. 3-0 with 52 minutes gone.

'You might as well go home,' sang the Blues support to the home contingent. They couldn't have been more correct.

Belletti skied a chance over after he was set-up by the in-form Kalou. Lampard then drove a shot straight at Turnball but he did not have to wait long to celebrate his move into the top 10 Chelsea appearance makers with a goal; typically surging into the box to meet Kalou's cross unmarked and head beyond the keeper's right arm.

That was the 63rd minute. Goal number five came on 66. Anelka cut in from the right, his shot was straight at Turnball but the keeper joined a day of dodgy home form by spilling it onto the post for Malouda to snap up a gift.

Hundreds were heading for the exit even before that goal and it might have become thousands had Anelka not been offside when he turned in a Malouda cross.

Deco replaced Lampard with 18 minutes remaining and with his first ball forward he put Anelka in for a shot. The keeper this time did well to stop it.

Kalou, with his first Chelsea hat-trick in sight, curled an ambitious attempt over on 73 minutes.

So Scolari's men had to settle for five. The last time we netted that many on Teesside was back in 1929 and that was a narrow 4-5 win. Today, the two sides weren't even remotely close.

Chelsea (4-1-4-1): Cudicini; Bosingwa, Alex, Terry (c), Bridge (Ferreira 65); Mikel; Kalou, Belletti, Lampard (Deco 72), Malouda; Anelka (Sinclair 78).
Scorers Kalou 13, 52, Belletti 50, Lampard 63, Malouda 66.

Middlesbrough (4-4-1-1): Turnbull; Grounds (J Johnson 54), Riggott, Wheater, Taylor; A Johnson (Alves 64) O'Neil, Shawky (Digard 64), Downing (c); Aliadière; Mido.
Booked O'Neil 26, Alves 76.