This was Sunderland's first top-flight win since December 2002 and their fans celebrated in style after the final whistle.
There was joy on Wearside but gloom on Teesside and Merseyside. The Black Cats' win left Everton at the bottom of the table.
Sunderland battled hard and deserved the points.
Middlesbrough promoted reserve keeper Brad Jones with Mark Schwarzer ruled out with a shoulder injury, but the youngster had the misfortune to have to pick the ball out of the net in the second minute.
Tommy Miller, who returned to his native north east from Ipswich Town in the summer, stunned the home crowd with a shot that went in off a post following a mix-up in the home defence as they attempted to deal with a long ball.
Middlesbrough hit back but Franck Queudrue saw a drive strike visiting skipper Gary Breen.
Sunderland keeper Kelvin Davis has come in for some flack this season for costly mistakes, but he rose to this occasion in style and kept his side in the game before the interval.
Davis denied James Morrison with an outstretched hand in a one-on-one situation, with an equaliser on the cards. He then brought off two more fine saves.
As well as being a goal down at the break, Middlesbrough also lost central defender Ugo Ehiogu to injury. Ironically, the former England international had expressed his hopes for an injury free run in the programme.
Davis was by far the busier goalkeeper in the first half and it looked as though he would be under more pressure after the break. The visitors, however, defended well to protect their goal.
Julio Arca sent Sunderland's fans wild when he increased their lead on the hour with a brilliant free-kick. From the edge of the penalty area Arca left Jones helpless with a left-foot shot into the corner of the net.
Boro fought desperately to pull the game around but a resilient Sunderland defence kept them at bay to secure a morale-boosting victory.
Steve McClaren's side must now look to bounce back in Thursday's UEFA Cup tie against Xanthi in Greece.