Manchester United regained top spot in the Premier League as goals from Wayne Rooney and Park Ji-Sung secured a 2-1 win over arch rivals Liverpool on Sunday.
Sir Alex Ferguson's team responded to an early opening goal from Fernando Torres to earn a victory which ends Liverpool's run of three straight wins in this fixture and maintains United's quest to win a 19th English league title.
The champions are now two points ahead of second placed Arsenal with seven games to play.
The opening 10 minutes at Old Trafford were among the most incident-packed, and contentious, of the Premier League season as the ill-feeling between the two old enemies became abundantly apparent.
First blood was drawn by Liverpool with a superbly-worked goal that suggested their hopes of another win over the defending champions might not be that far-fetched.
Steven Gerrard drove deep into United territory from just inside his own half before
feeding the ball to Dirk Kuyt whose run continued to the right-hand by-line before he pulled back a pinpoint cross, which found the head of Torres, inexplicably unmarked six yards from goal, for a routine finish.
Old Trafford was stunned but it took just seven minutes for the home side to respond, the equaliser coming after Emiliano Insua made a weak defensive header which saw the ball fall for Antonio Valencia.
He immediately set off towards the Liverpool goal, with Javier Mascherano snapping at his heels and bringing him down just as he entered the area.
Referee Howard Webb pointed to the spot and immediately brandished a yellow card at the Liverpool midfielder, with United players surrounding the official and demanding he show red.
Gary Neville sprinted half the length of the field to voice his opinion and engaged in an angry exchange with Jamie Carragher, one duplicated on the touchline by rival managers Ferguson and Rafa Benitez who engaged in a finger pointing spat before the United boss screamed his disapproval at Webb.
After the rows, Rooney's poor penalty was well saved by Jose Reina but the rebound falling kindly for the England forward, who was alert enough to turn the loose ball into the open net for the equaliser.
Perhaps understandably, the early intensity was not maintained but United remained on top.
Park placed a pair of headers wide of the Liverpool goal and Nani's strong run ended with a powerful shot from the edge of the box which Reina turned around his post.
Just before the interval, Carragher was booked for a foul on Darren Fletcher and Rooney produced a 25-yard free-kick which Reina caught easily, but such opportunities were rare.
Park had endured an ineffective first half, playing just behind United's lone striker Rooney, but the second period began in very different fashion for the South Korean, who soon made room for himself on the edge of the area and unleashed a shot which forced Reina to save.
However, just before the hour, the Liverpool goalkeeper had no chance with Park's next attempt - a clinical, diving header from no more than six yards which put the home side in front.
Rooney had started the move with an intelligent pass to Fletcher on the right wing and the Scotsman's delivery was inch-perfect.
The earlier threat of violence re-surfaced in the 67th minute when Fletcher was tripped by Kuyt and retaliated with a kick at the Dutchman which should have brought a yellow, or even red, card but which saw both players merely lectured by Webb.
Rooney chipped over and Benitez introduced Alberto Aquilani and Ryan Babel as Liverpool tried desperately to find some attacking impetus.
But Torres wasted their best hope of an equaliser in the final minute when he completely miscued from eight yards and Yossi Benayoun headed meekly at van der Sar.