Manchester United made it a record 11 Premier League clean sheets as they thrashed West Brom at The Hawthorns.
Dimitar Berbatov’s angled finish put them ahead after 22 minutes, with Albion’s Paul Robinson sent off before half-time for fouling Ji-Sung Park.
Carlos Tevez tapped in seconds before the break after Scott Carson dropped Ryan Giggs’ free-kick, and Nemanja Vidic headed home a third on the hour.
Cristiano Ronaldo then struck twice in eight minutes to seal United’s win.
It gave Sir Alex Ferguson’s side a three-point lead ahead of Liverpool in the title race, with the added bonus of topping up their goal difference in style.
United goalkeeper Edwin van der Sar has now gone 1,032 minutes without conceding, beating the previous record set by Chelsea’s Petr Cech five seasons ago.
Albion and their fans were furious with the performance of referee Rob Styles, particularly his decision to send off Robinson, but the brutal reality was that they were outclassed by a United side that looked in ominously good order.
United were lifted by the return of Rio Ferdinand after a back injury – but he was rarely required as the champions strolled to victory.
Jay Simpson looked lively early on for Albion, but United always carried the greater threat and it was no surprise when they carved out the opener.
Michael Carrick exchanged passes with Berbatov and the Bulgarian completed the formalities with a powerful angled finish past Carson.
Tevez should have doubled United’s lead three minutes later, but he turned Ronaldo’s cross just wide at the near post.
Ronaldo was also guilty of squandering a glorious opening when he chipped over Carson when clean through, but his effort rolled wide.
The huge task facing Albion was made even tougher five minutes before the interval when Robinson was shown a red card by referee Styles for a meaty challenge on Park.
It did not look like he had his foot raised and he appeared to get the ball, but Styles saw differently and enraged The Hawthorns by sending off the experienced defender.
The game was effectively over as a contest seconds before the interval when Carson dropped Giggs’ free-kick at the feet of Tevez six yards out, the Argentine slotting home a simple finish.
Albion’s last hope of a lifeline disappeared when Ryan Donk’s powerful shot struck an upright and rebounded to safety after 57 minutes.
United got their third on the hour when Vidic arrived to power a corner from Giggs past Carson.
It was now a case of damage limitation for Albion – but United were not in the mood to allow them even that small mercy.
The fourth came after 65 minutes when Tevez released Giggs, who timed his pass to perfection for Ronaldo to score with a precise right-foot finish.
Ronaldo was on target again eight minutes later when Berbatov, who looked suspiciously offside, played him in to beat Carson through his legs.
It was time for some changes from United, with Ferguson giving a debut to new Serbian signing Zoran Tosic.
It was a comfortable night for United – but not for rivals Liverpool and Chelsea who play on Wednesday.
West Brom: Carson, Hoefkens, Pele, Donk, Robinson, Zuiverloon (Morrison 64), Borja Valero, Koren, Brunt, Simpson (Bednar 64), Fortune (Cech 46).
Subs Not Used: Kiely, Kim, Dorrans, Filipe Teixeira.
Sent Off: Robinson (40).
Booked: Koren, Bednar, Carson, Donk, Morrison.
Man Utd: Van der Sar, Neville (Eckersley 71), Ferdinand (Brown 70), Vidic, O’Shea, Park, Carrick, Giggs, Ronaldo, Berbatov (Tosic 77), Tevez.
Subs Not Used: Kuszczak, Scholes, Fletcher, Gibson.
Booked: Park, Carrick.
Goals: Berbatov 22, Tevez 44, Vidic 60, Ronaldo 65, 73.
Ref: Rob Styles (Hampshire).