A 10th league title under Sir Alex Ferguson remains Manchester United's to lose, but they came close to doing just that yesterday during a frantic match on snowy Teesside that returned some dramatic tension to the race to the top.
The two managers, Ferguson and Gareth Southgate, embodied the aggressive anxiety around a fascinated Riverside with a finger-pointing spat, though afterwards Ferguson gave credit to the hosts for their contribution to " a fantastic match" and Southgate said their dispute was caused by confusion over two different decisions. "I have complete respect for him," Southgate said, "but it's important I don't back down in these situations."
Backing down was not part of the Middlesbrough psyche yesterday and as a consequence Ferguson's mood was positive.
He knew this was a game United "could have lost", and so Wayne Rooney's 74th-minute equaliser should be viewed as a point grabbed. But for that, United's grip would have slipped; because of it, they departed south three points ahead of Chelsea.
That could look slender given United have yet to go to Stamford Bridge, but their goal difference gives them a telling advantage. "It could prove to be a vital point," Ferguson said. "Our goal difference is good. But we cannot take anything for granted."
Scoring important late goals is a United trait and Ferguson saluted his players' defiance on a difficult day. Accepting that defensively the visitors were "haphazard", he said: "The nature of this club is that we never give in and that's a great quality to have at this time. That sends out a signal to other players and fans. We will stretch ourselves in every game."
They were stretched to breaking point here and it was the back four which took the strain. Rio Ferdinand limped off in the 70th minute and is now a doubt for Roma on Wednesday night. Ferdinand left the stadium with a plastic cast on his left foot.
With Nemanja Vidic already out, that would be a blow, though a two-goal lead offers some protection. But Ferguson would not want to be without the pair for Arsenal's visit to Old Trafford on Sunday.
Because "haphazard" was the correct assessment of United's defending. So assured when Vidic is present, the Serb's absence allowed the concession of a league goal for the first time in eight hours and 16 minutes stretching back over six games to 23 February. Vidic had appeared in all of those clean-sheet games.
Missing Vidic, United began with Ferdinand partnering John O'Shea. They ended with Wes Brown alongside substitute Gerard Pique. No matter the combination, it was unconvincing and both of Boro's goals came through the middle.
Afonso Alves scored both of them, his first for Boro since his £12m move from Heerenveen. The Brazilian has been damned a little prematurely – this was only his second start in the league and he has yet to complete 90 minutes – and as Southgate put it, Alves offered "a glimpse of what he's capable of". Both goals were coolly taken.
The first was a 35th-minute equaliser. United had eased ahead on 10 minutes via Cristiano Ronaldo's 37th goal of a remarkable season. Ryan Giggs's corner ran deep to Michael Carrick who returned the ball to the six-yard box where Ronaldo spiked it past Mark Schwarzer. A simple goal and the promise of an uncomplicated afternoon.
But against the top four, Boro are better than most. Having started with Alves alone, Jérémie Aliadière was pushed up front and the Frenchman should have scored in the 23rd minute when set free by Julio Arca's typically astute pass.
The game was open and Ronaldo almost capped a mazy run with a second goal. Then Alves warmed Edwin van der Sar's fingers with a free-kick and Aliadière atoned when winning a header above Ferdinand that teed up Alves.
With O'Shea nowhere, Alves tucked the ball away. It was 1-1 and game on. O'Shea was shunted to right-back.
Before half-time there was a chance for Stewart Downing at one end and then a penalty claim against Andrew Taylor at the other. Less than a minute of the second half had elapsed when Carrick was forced to block Emanuel Pogatetz's close-range effort. It was compelling action.
The Riverside's biggest crowd of the season was then rewarded with Alves' second. Again Aliadière played a part, jumping against Brown and getting the better of the ricochet. That took the ball into Alves' path and he steered a shot into the far corner. If he felt under pressure, Alves was not showing it.
Three minutes later Ferdinand had to dive in front of Alves' goalbound header and a first league defeat since Manchester City's victory at Old Trafford was staring at the champions.
But the power of their squad was seen when Park Ji-Sung stepped off the bench, cut inside Taylor and drilled the ball low across to Rooney. Schwarzer might have saved Rooney's shot but for a deflection off David Wheater.
Even then substitute Tuncay Sanli might have won it for Boro at the death. " I'm really proud," Southgate said, "we had them rattled."
Goals: Ronaldo (10) 0-1; Alves (35) 1-1; Alves (56) 2-1; Rooney (74) 2-2.
Middlesbrough (4-4-1-1): Schwarzer; Young, Wheater, Pogatetz, Taylor; Aliadière (Johnson, 90), Boateng, Arca, Downing; O'Neil; Alves (Tuncay, 78). Substitutes not used: Turnbull (gk), Grounds, Cattermole.
Manchester United (4-3-3): Van der Sar; Brown, Ferdinand (Pique, 70), O'Shea (Hargreaves, 67), Evra; Carrick, Scholes, Giggs; Ronaldo, Tevez (Park, 63), Rooney. Substitutes not used: Kuszczak (gk), Anderson.
Referee: M Riley (West Yorkshire).
Booked: Middlesbrough Young, Boateng, O'Neil; Manchester United Rooney.
Man of the match: Boateng.