Second-half strikes from Ramires and Victor Moses saw an under-strength Chelsea beat Middlesbrough 2-0 in their FA Cup fifth-round match at The Riverside.
The Premier League club field a weakened side from that which lost 2-0 at Manchester City at the weekend, and it showed as they served up a poor example for a side of their means in a dire first half.
Chelsea improved in the second period though, as Ramires fired in a curler to open the scoring, while Moses added a second after a delightful one-two between Oscar and Eden Hazard.
The Blues now face runaway Premier League leaders Manchester United at Old Trafford on March 10 for a place in the semi-finals.
Rafael Benitez will be pleased with the victory, but the overall performance was not impressive against a Boro side in Championship freefall after a promising start to the season.
A turgid first half saw Chelsea struggle to string two passes together, unsurprising given they had made eight changes from the weekend.
Boro, meanwhile, had more possession but have serious injury problems of their own and were equally disjointed, with their fitness woes worsening after Andre Bikey pulled a hamstring midway through the half.
The hosts did have the better chances though, Scott McDonald heading wide from an excellent Nicky Bailey cross, and Mustapha Carayol almost beating a nervy Petr Cech with a bouncing drive.
That was more than could be said for Chelsea who, with no Juan Mata or Frank Lampard, were relying on Fernando Torres and Moses to combine well: they did not, and the Blues’ best effort was an Oscar cross-shot that landed just past the far post.
There was a bit more about Chelsea as the second half got underway, the visitors more direct and enthusiastic in their attacking approach.
The renewed vigour paid early dividends as Ramires found the back of the net with a curling effort that may well have taken a vital deflection off Torres as it whistled into the top right.
The chance was initially created by Oscar’s fantastic run and cross from the right, and the Brazilian continued to wreak havoc as he filled the space on the wing that had been vacated by Moses, who was operating more centrally.
Indeed, Chelsea were a far better proposition now, as Torres saw a vicious drive deflected just over the bar, while Ramires mis-kicked one effort and had another thunderbolt blocked.
Boro responded by introducing Ishmael Miller into the mix, and the match promptly disintegrated back into the slug-fest of the first half.
But a moment of brilliance cemented Chelsea’s lead as, not long after coming on as a substitute, Hazard went on a driving run before exchanging a one-two with Oscar, whose marvellous backheel sent the Belgian clean through. Unselfishly, Hazard rolled the ball to Moses, who finished easily.
Oscar almost added a third with a solo run and low drive wide, but Chelsea eased off a touch in the latter stages, Boro twice going close as Seb Hines put a header just wide and Miller volleyed just over when both should have made Cech work.
Miller had a fierce drive tipped over by Cech in the final minute of the 90, but was all too late for Tony Mowbray’s men though, as Chelsea comfortably sealed their progress.
MAN OF THE MATCH
Ramires (Chelsea) – Probably the only good all-round performance, he covered well for some repeated sloppy play by team-mates, scored a good goal and was always involved in attack and defence.
MIDDLESBROUGH: Steele 6, Bailey 5, Friend 6, McManus 6, Bikey 6, Williams 6, Haroun 5, Leadbitter 6, McDonald 6, Main 5, Carayol 6; Subs: Zemmama 6, Hines 6, Miller 6.
CHELSEA: Cech 6, Ferreira 6, Ivanovic 6, Terry 6, Bertrand 6, Ramires 8, Ake 6, Moses 7, Oscar 7, Benayoun 5, Torres 5; Subs: David Luiz 6, Hazard 7, Marin N/A.