Ronaldo scores from the spot to haul Man Utd level
Cristiano Ronaldo's penalty earned Manchester United a replay after Middlesbrough threatened a shock in the FA Cup quarter-final at the Riverside.
United lost keeper Edwin van der Sar in the warm-up, but Wayne Rooney's low drive put them ahead after 23 minutes.
Lee Cattermole volleyed Middlesbrough level on the stroke of half-time.
George Boateng headed Boro's second a minute after the interval, but then handled Rio Ferdinand's header after 66 minutes and Ronaldo equalised.
The replay will be at Old Trafford on 19 March, giving England coach Steve McClaren a fixture headache as he prepares to fly out with his squad to Tel Aviv for the Euro 2008 qualifier against Israel.
McClaren must now hope influential figures such as Gary Neville and Wayne Rooney emerge unscathed.
United suffered a set-back before kick-off when Van der Sar suffered a calf injury in the warm-up and was replaced by Tomasz Kuszczak.
He was quickly in action, making a vital block from Stewart Downing as he raced on to Julio Arca's pass.
United settled, however, and took the lead after 23 minutes when Rooney drove in a low shot following good work by Ryan Giggs.
Middlesbrough remained a threat and almost equalised six minutes later when Yakubu out-muscled Rio Ferdinand and brought another fine save out of Kuszczak.
What do you think? Rate the players
Giggs thought he had doubled United's lead 10 minutes before the interval when his shot from Gary Neville's cross beat Mark Schwarzer but bobbled to safety off an upright.
It was a reprieve for Middlesbrough and they took full advantage to draw level on the stroke of half-time.
Kuszczak only half-cleared, and when Arca headed the ball back into the danger zone, Cattermole controlled cleverly and volleyed home on the turn.
And the turnaround was complete a minute after the interval as Boateng rose unchallenged at the far post to head Downing's corner past Kuszczak.
United were suddenly in trouble, and they saw desperate penalty appeals waved away as Rooney tumbled under challenge from Stuart Parnaby.
But Boateng was the villain after 66 minutes when he handled Rio Ferdinand's header - referee Rob Styles pointed to the spot and Ronaldo coolly slotted home the penalty.
Middlesbrough: Schwarzer, Parnaby, Woodgate, Pogatetz, Taylor, Cattermole (Morrison 80), Boateng (Euell 89), Arca, Downing, Yakubu, Viduka (Lee 89).
Subs Not Used: Jones, Xavier.
Goals: Cattermole 45, Boateng 47.
Man Utd: Kuszczak, Neville, Ferdinand, Vidic, Heinze, Ronaldo, O'Shea, Carrick, Giggs, Rooney, Larsson.
Subs Not Used: Brown, Park, Smith, Richardson, Eagles.
Goals: Rooney 23, Ronaldo 68 pen.
Ref: R Styles (Hampshire).