Giving with one hand and taking away with the other, Manchester United offered a glimpse of frailty yesterday while illustrating the depth of their resilience. A vibrant 2-2 draw with Middlesbrough brought a flawed, if engaging performance, providing their title rivals with a glimmer of hope, but they retain a determination to maintain their preeminence.

Having grasped an early advantage through Cristiano Ronaldo’s 37th goal of an extraordinary season, United went adrift in the snow against Gareth Southgate’s enterprising team. Two goals for Afonso Alves, the first since his club-record £12 million transfer from Heerenveen in January, put Middlesbrough ahead before Wayne Rooney secured a point that Sir Alex Ferguson believes may be “vital”.

United’s lead over Chelsea is three points. They host Arsenal at Old Trafford next weekend and must travel to Stamford Bridge, but fear is not in their nature. With Rio Ferdinand leaving Teesside sporting a plastic protective cast on his left foot, they have trials to overcome, but Ferguson proclaimed himself largely content at his team’s contribution to a superb match.

“We could have lost the game and they had some chances, but on the other hand we could have won because the quality of our football was terrific at times,” the United manager said. “We were in control. It became a great game of football when [Middlesbrough] changed their shape and both teams deserve credit for producing a game like that at this time of year.”

Middlesbrough’s opening goal was the first United had conceded for eight hours and 16 minutes stretching back to February 23, but the champions were far from impregnable. Without Nemanja Vidic, who was injured during the 2-0 victory over AS Roma last week, their defending was brittle. “We were bit haphazard,” Ferguson said.

The Scot attempted to rectify matters at half-time by switching Wes Brown to centre back and John O’Shea to right back – and later by withdrawing the Irishman in favour of Owen Hargreaves – but Afonso carried a burly threat that United struggled to contain.

Having conceded parity in the tenth minute, Middlesbrough regrouped. Afonso tested Edwin van der Sar’s reflexes with a long-range free kick, Jérémie Aliadière dragged a shot wide when well placed and Stewart Downing brought a fine reactive save from the United goalkeeper. There were further opportunities after the interval. Michael Carrick cleared an Emanuel Pogatetz effort off the line and Downing hit the side-netting. “We had them rattled,” Southgate said. “We had them on the back foot.”

It has taken Afonso time to adjust to English football, but in only his second league start, the striker was imperious. The Brazil international took his goals clinically, twice running on to long balls which had been flicked forward by Aliadière, scoring first with his left foot and then with his right.

“From his point of view, we’ve been waiting for lift-off,” Southgate said last night. “We’ve seen on the training ground that he’s a finisher and his finishing today was outstanding. I’m not bothered that he’s missed chances. He’s given a glimpse of what he’s capable of and he looks sharp.”

The 27-year-old did not argue. “Of course, it was a dream come true to score against Manchester United, but I want to do the same against other teams as well,” Afonso said. “I needed time and patience, but I knew the goals would come. I knew it was only a matter of time. I’m happy I scored, but I would have had more to smile about if we’d won.”

Such satisfaction from Middlesbrough appeared unlikely when, from a Ryan Giggs corner, Carrick’s square pass allowed Ronaldo to score his 27th league goal in as many starts. The Portuguese also skidded around three red shirts before shooting wide and at that stage the Riverside Stadium’s biggest crowd of the season must have been expecting a rout. Yet United’s authority drained away, not returning until the latter moments. In the 74th minute, with Southgate’s players tiring, Park Ji Sung, a substitute, fed the ball to Rooney, whose shot took a deflection off David Wheater. Mark Schwarzer, the Middlesbrough goalkeeper, also spilt a Rooney header.

With Southgate and Ferguson confronting each other on the touch-line, the afternoon was not without controversy. United should have had a penalty when Andrew Taylor handled a shot from Ronaldo on the cusp of the interval, but Middlesbrough persevered. “We’ve thrown it open a bit today, which is good for the league,” Southgate said. “I’m proud of my players.”

How they rated

Middlesbrough (4-5-1): M Schwarzer 6 L Young Y 7 D Wheater 6 E Pogatetz 7 A Taylor 6 J Aliadière 7 G O’Neil Y 7 G Boateng Y 8 J Arca 7 S Downing 7 Afonso Alves 8 Substitutes: Tuncay Sanli (for Afonso, 78min), A Johnson (for Aliadière, 90). Not used: R Turnbull L Cattermole, J Grounds. Next: Tottenham (a).

Manchester United (4-3-3): E van der Sar 6 W Brown 5 R Ferdinand 5 J O’Shea 4 P Evra 5 P Scholes 7 M Carrick 6 R Giggs 5 C Ronaldo 6 W Rooney Y 7 C Tévez 5 Substitutes: Park Ji Sung 5 (for Tévez, 63min), O Hargreaves 5 (for O’Shea, 67), G Pique 6 (for Ferdinand, 70). Not used: T Kuszczak, Anderson. Next: Arsenal (h).