Cesc Fabregas came off the bench to score a last-minute penalty to earn 10-times winners Arsenal a 1-1 home draw with Championship (second division) side Leeds United in a pulsating FA Cup third-round match on Saturday.
Three other Premier League clubs were not so lucky, with Sunderland, West Bromwich Albion and Blackpool losing to lower-league opposition as the world's oldest cup competition maintained its reputation for upsets.
Sunderland, flying high in sixth position in the league, fielded a weakened team and were beaten 2-1 at home by Notts County who are struggling in League One (third division).
Championship promotion-chasers Reading won 1-0 at home to hand West Brom their sixth successive defeat while League One Southampton overcame visiting Blackpool 2-0.
Bolton Wanderers, seventh in the Premier League, needed late goals from Kevin Davies and Johan Elmander to scrape past minor league York City 2-0 while Everton, Fulham, Wigan Athletic, Aston Villa, West Ham United and Birmingham City also progressed.
On Sunday, holders Chelsea entertain Ipswich Town while Kenny Dalglish's first game back in charge of Liverpool could hardly be bigger as he takes his side to Old Trafford to face Manchester United.
Last year Manchester United lost at home in the third round to Leeds, then in League One.
The Yorkshiremen looked on course for another upset win at The Emirates in Saturday's lunchtime kickoff when Denilson tripped Max Gradel in the 54th minute and Robert Snodgrass converted the penalty in front of 8,000 travelling fans.
Arsenal, unbeaten in 28 home FA Cup games since Leeds won at their old Highbury ground in 1997, threw on their big names in an effort to save the tie.
When substitute Theo Walcott was pulled back by Ben Parker up stepped Fabregas to stroke in a 90th-minute spot kick.
In stoppage time Kasper Schmeichel saved brilliantly from Denilson before Nicklas Bendtner had a fabulous chance to win it for Arsenal only to screw his shot badly wide.
"I felt today our game was a bit slow in our passing, we were not sharp in our decision-making, the rest is credit to Leeds. They stopped us from playing," manager Arsene Wenger told the club's website.
"When Cesc comes on he has that vision so even if he is closed down he doesn't have to run too much to make the game quicker.
"It was a very difficult game because it was a real Cup game and Leeds were up for it, they played well.
It was important ... not to go out today because that would have been a shocker," added Wenger.