Chelsea march on into the FA Cup quarter-finals courtesy of a hard-fought 2-0 win at the Riverside Stadium.
After a slow first half with few chances at either end, Ramires gave us the lead five minutes after the break when his strike deflected off Fernando Torres and beat the despairing dive of Jason Steele in the Middlesbrough goal.
Torres then missed two good chances to put the game out of sight, before Victor Moses scored our second after excellent build-up play from the substitute Eden Hazard.
A trip to take on Manchester United at Old Trafford a week on Sunday now awaits, and given our recent record in the competition, supporters will head to the north west in optimistic mood.
Rafael Benitez made a host of changes for our first visit to the Riverside Stadium since 2008.
Branislav Ivanovic was the only defender to keep his place in the side from Sunday's defeat at Manchester City, with John Terry, Paulo Ferreira and Ryan Bertrand coming into the side. Gary Cahill was suffering with a virus, while Cesar Azpilicueta had a pain in his leg.
Young Dutchman Nathan Ake, meanwhile, was handed his full debut in midfield alongside Ramires, while there was also a rare start for Yossi Benayoun.
In attack, Torres, a late substitute at the weekend, was given the nod ahead of Demba Ba.
Josh McEachran, currently on loan at Middlesbrough from the Blues, was ineligible, while Tony Mowbray was shorn of the services of both Jonathan Woodgate and Kieron Dyer through injury.
With both sides having been beaten at the weekend, starting the game well was imperative, and it was the Blues who threatened first.
Ramires picked the ball up from Terry, before evading two challenges and feeding Oscar to his right; the Brazilian attempted to pick out Torres in the six-yard box but his cross, while dangerous, had slightly too much pace on it for the striker.
The Blues were looking threatening in the final third early on, and shortly after Torres had fired across the face of the goal we should have taken the lead.
Moses displayed a wonderful combination of pace and power down the right-hand side, easing past George Friend, before pulling his ball back into the path of Oscar, who had made a lung-busting run from deep, but with no time to adjust his footing, the shot was comfortable for Steele to deal with.
The home supporters had turned up in large numbers for what was arguably Middlesbrough's biggest game of the season so far, but with Terry back in the side, and marshalling our defence in his trademark manner, they had little to cheer in the opening 20 minutes.
Middlesbrough v Chelsea
Their first attempt on goal, however, was a serious one. Faris Haroun, who had started on the left wing before switching to the right, did well to hold off both Bertrand and Ake, and as he crossed into the penalty area Scott McDonald, the smallest player on the pitch, powered his header inches past Petr Cech's post.
After a positive opening spell, we'd tailed off, and the Championship side were beginning to see more of the ball.
Cech was then forced into his first real save of the night low down from a powerful strike by Mustapha Carayol, and the Chelsea goalkeeper was grateful to see Terry clear the danger after he struggled to hold the initial shot.
As the players headed back inside at the break, Benitez had plenty to ponder.
Both managers opted against making any changes to personnel at half-time, and five minutes into the second half we finally made the breakthrough.
Oscar's cross from the right was cleared away, and as the ball fell to Ramires, he fired towards goal; the ball took a wicked deflection off Torres and flew into the top corner of the net, giving Steele no chance.
Middlesbrough v Chelsea
It was a goal which sparked us into life, and barely a minute later Torres should have scored again, dragging his shot agonisingly wide of Steele's post after being put clean through.
The Blues were beginning to take control of the game, and moments later the Spaniard again beat the offside trap, but again the home side breathed a sigh of relief as Torres' strike flew inches over the bar.
Just before the hour mark Benitez freshened up our attack, introducing Hazard at the expense of Benayoun.
The Belgian took up his familiar position out wide on the left, and he was unfortunate not to double our advantage with a sweet curling effort after linking up well with Ramires.
Hazard was causing Mowbray's side all manner of problems, and it was from another fine run from by the substitute that we went 2-0 up with 17 minutes remaining.
After picking the ball up deep inside the Middlesbrough half, Hazard drove into the penalty area, exchanging passes with Moses before lifting the ball over Steele for Moses to roll into an empty net.
Middlesbrough v Chelsea
It was to prove the Nigerian's final contribution as he was replaced by David Luiz, while Benitez made his final change of the night shortly after, replacing Oscar with Marko Marin.
Middlesbrough, to their credit, refused to cave in, and they went close twice in quick succession, first from a Stephen McManus header and then from a Carayol volley which beat Cech but sailed over the bar.
Chelsea saw the game out safely, however, and our unbeaten FA Cup record in open play now stretches to 27 matches.
Chelsea (4-2-3-1): Cech; Ferreira, Ivanovic, Terry (c), Bertrand; Ramires, Ake; Moses (David Luiz 75), Oscar (Marin 79), Benayoun (Hazard 58); Torres.
Unused substitutes: Turnbull, Cole, Lampard, Ba.
Scorers Ramires 50, Moses 72
Middlesbrough (4-4-2): Steele; Bailey, Bikey (Hines 35), McManus, Friend; Haroun, R Williams (c), Leadbitter, Carayol (Zemmama 73); Main (Miller 62), McDonald.
Unused substitutes: Leutwiler, Emnes, Ledesma, Smallwood.
Booked McManus 74, Bailey 86
Referee Martin Atkinson