Manchester United suffered a damaging 1-1 draw with Newcastle at Old Trafford after Demba Ba's controversial penalty earned a point for the 10-man visitors on Saturday.
Sir Alex Ferguson's second-placed side are four points behind Manchester City and that gap will extend to seven if the leaders win at Liverpool on Sunday, so it was no surprise the United boss was fuming at full-time.
Javier Hernandez had given United the lead just after half-time but Ba levelled after referee Michael Jones took his assistant's advice to award a penalty for Rio Ferdinand's challenge on Hatem Ben Arfa.
Newcastle played the last 12 minutes of the game with 10 men, after Jonas Gutierrez's dismissal for a second yellow card for a clumsy foul on Nani.
But, despite intense pressure and a 94th-minute Hernandez goal ruled out for offside, the home side could not record a much-needed victory.
Wayne Rooney, back from a hip injury, was involved in an early incident when he hacked at a loose ball on the ground and accidentally kicked Fabricio Coloccini in the 26th minute.
Newcastle's Ben Arfa needlessly became involved and angrily pushed at Rooney, earning the game's first yellow card for his troubles.
The incident seemed to inject some energy into the home team, with Nani feeding Hernandez for a wild shot over and Newcastle goalkeeper Tim Krul superbly keeping out a deft flick from Ryan Giggs.
United's opening goal, after 49 minutes, owed much to a large slice of fortune after Newcastle central defender Steven Taylor was judged to have brought down Hernandez on the edge of the penalty area.
Rooney took the ensuing free-kick, kicking directly into the wall before attempting a second shot from the rebound.
The ball was blocked by Taylor but his clearance struck Hernandez and ricocheted back into the Newcastle goal from point-blank range.
Immediately afterwards, Fabio was played through by Hernandez and easily beat Coloccini before firing over the bar and an Ashley Young corner was helped on for Rooney to head over from seven yards.
After 55 minutes, the contest could have been effectively decided as Patrice Evra squared the ball for Young, who took a touch and his time on the way into a shooting position, only to miss wide of the right-hand post.
But there were warnings signs from the visitors, with a well-worked corner being kept in at the far-post by Taylor to allow Coloccini a shot from seven yards that was magnificently tipped over by David de Gea.
However, Newcastle drew level when Ferdinand tackled Ben Arfa after 61 minutes and, after consulting with his assistant John Flynn, Jones pointed to the penalty spot, to the horror of the home side's players.
Ba kept his composure well during the two-minute delay before placing the penalty kick into the bottom right-hand corner.
The half hour that followed was full of intense United attacking play, especially after Gutierrez was sent off.
Rooney made room for a wayward shot soon after the equaliser and Nani's impressive run almost presented Young with a scoring chance.
Krul saved superbly from a Nemanja Vidic header following Giggs' free-kick awarded after Gutierrez's dismissal, then the Newcastle keeper launched himself to turn away Evra's 18-yard strike.
Nani's 85th-minute cross found an unmarked Young, whose low drive struck the foot of the post, while ex-United defender Danny Simpson somehow managed to clear Hernandez's header off the line as the forward met a cross from Fabio.
United thought they had grabbed a winner in injury time, but Hernandez's tap-in from a low Giggs cross that was touched on by Michael Carrick was chalked off for offside.