Manchester United overcame the sending-off of England defender Gary Neville to beat neighbours Manchester City 4-2 in an action-packed FA Cup fifth-round match at Old Trafford on Saturday.
Two goals by Ruud van Nistelrooy and one each for Paul Scholes and Cristiano Ronaldo put the champions, reduced to 10 men for nearly an hour, into the quarter-finals for the first time since 1999.
They were joined in the last eight by Millwall, who edged out fellow first division side Burnley 1-0, and second division Tranmere Rovers, who beat third division Swansea City 2-1.
Premier league sides Fulham and Birmingham City were held to draws by first division West Ham United and Sunderland respectively.
Manchester United, who suffered a shock 3-2 home defeat by Middlesbrough on Wednesday to damage their chances of retaining the premier league title, fully deserved their derby victory.
"In the first half we were outstanding and should have been three or four up," United manager Alex Ferguson told Sky Sports. "The sending-off changed the nature of the game but in the second half our counter-attacking was outstanding. Our character and discipline were very good."
United dominated the first half and went ahead after 34 minutes when midfielder Scholes tapped the ball in from close range after a slick passing move.
But the hosts were reduced to 10 men within minutes, Neville appearing to head-butt City's Steve McManaman after the United defender had fallen over in the penalty area.
"It was uncharacteristic of Gary and he let himself down," Ferguson said.
BRILLIANT SAVES
City, who recovered from 3-0 down at halftime with 10 men to beat Tottenham Hotspur in the last round, scented a rare victory over their local rivals and United goalkeeper Tim Howard made brilliant saves to deny McManaman and Joey Barton.
But United, record 10-times FA Cup winners, rode the storm and increased their lead after 71 minutes through the prolific Van Nistelrooy.
The Dutch striker pounced at the far post to tap in a teasing cross by Ronaldo and the Portuguese winger then turned the ball in from a tight angle after Ryan Giggs's firm volley was well parried by goalkeeper Arni Arason.
City defender Michael Tarnat pulled one back 12 minutes from time with a powerful angled strike but Van Nistelrooy settled the match with a simple tap-in after Roy Keane, an inspirational captain throughout, headed back a deep cross.
Striker Robbie Fowler grabbed another late consolation with a quickly taken free kick but City, 16th in the premier league table, were left to concentrate on their struggle to avoid relegation.
Mikael Forssell put Birmingham ahead at Sunderland with a well taken goal after 28 minutes but Kevin Kyle earned the hosts a 1-1 draw with a glancing header before halftime.
Birmingham midfielder Aliou Cisse was sent off for a second booking in injury time.
Fulham goalkeeper Edwin van der Sar made a succession of fine saves to deny London rivals West Ham as a repeat of the 1975 Cup final, won 2-0 by the Hammers, ended in a goalless stalemate at Loftus Road.
Striker Danny Dichio headed Millwall's 70th-minute winner against Burnley, who had Paul Weller sent off, and Iain Hume sent Tranmere through with a fine 59th-minute strike to beat Swansea.
Premier league leaders and Cup holders Arsenal play third-placed Chelsea, Liverpool meet Portsmouth and Sheffield United tackle Colchester in the remaining fifth-round ties on Sunday.
The quarter-final draw takes place on Monday.
