A dramatic injury-time goal by David Bellion, with the ball appearing to come off his arm, salvaged a draw for Manchester United at Bolton.
United seemed set to lose after a mix-up between Tim Howard and Mikael Silvestre allowed Les Ferdinand to net.
Ferdinand's goal came after Kevin Nolan had equalised for Bolton, heading home after his initial shot was blocked.
Gabriel Heinze gave United a first-half lead on his debut, but it was not the perfect start he may have expected.
Heinze, who won gold with Argentina at the Olympics in Athens, looked impressive in his first appearance in a United shirt.
He slotted in comfortably at left-back and distributed the ball well from the back.
His display lit up an otherwise uninspiring first half in which United failed to impose themselves on their hosts.
Ruud van Nistelrooy made his first start of the season for United following an hernia operation and, despite showing signings of rustiness, was involved in some of his side's better moves.
For Bolton, Jay-Jay Okocha produced his customary flashes of brilliance, picking out his team-mates with ease although they failed to match his accuracy.
United looked ordinary going forward and Bolton appeared to have snuffed out any threat posed by the visitors, with Jussi Jaaskelainen blocking Paul Scholes' snap shot.
Bruno N'Gotty denied Van Nistelrooy a goalscoring opportunity, but conceded a corner from which United netted their opener on the stroke of half time.
Giggs whipped in the ball for Silvestre to head back into the danger zone where Heinze pounced and smashed home the first goal of his United career.
After the break, Sam Allardyce introduced El-Hadji Diouf into the fray and the Senegalese striker soon won a free-kick following a crude challenge from Phil Neville.
Ivan Campo picked out Okocha, who was given an age to despatch his shot on goal.
The Nigerian's attempt struck Nolan, forcing Howard into a reflex save but the ball rebounded to the striker and he headed into the empty net despite United's appeals for offside.
United were then lucky to not be further punished for some school-boy defending.
An error by Silvestre allowed Kevin Davies to exchange passes with Nolan and fire a shot from inside the area that went just inches wide of right-hand post.
Bolton took heart from their equaliser and proceeded to dominate thereafter, with Campo and Okocha testing the United defence.
Sir Alex Ferguson replaced the ineffective Kleberson with Ronaldo, and the Portuguese winger nearly stole the win for United.
He danced past the Bolton defence before unleashing a thunderbolt shot that Jaaskelainen brilliantly tipped onto the crossbar.
But the drama did not end there.
Phil Neville was penalised for a foul on Okocha on the halfway line and the Bolton man quickly took his free-kick.
There appeared to be no danger as Howard came out to collect the ball, but he failed to hold onto it and then a terrible mix-up between him and Silvestre gave second-half substitute Ferdinand the chance to grab a 90th-minute goal.
The veteran striker appeared to have wrapped up the win for Bolton, but United hit back very late on as they pumped the ball forward and Bellion got the final touch to send it over the line in dramatic fashion.
Bolton: Jaaskelainen, Hunt, N'Gotty, Jaidi, Barness, Campo, Nolan, Okocha, Speed (Hierro 87), Pedersen (Diouf 45), Davies (Ferdinand 75). Subs Not Used: Oakes, Ben Haim.
Booked: Okocha, Hunt.
Goals: Nolan 52, Ferdinand 90.
Man Utd: Howard, Phil Neville, Brown, Silvestre, Heinze, Kleberson (Ronaldo 64), Keane, Scholes, Giggs,
van Nistelrooy (Bellion 74), Smith. Subs Not Used: Carroll, Djemba-Djemba, Spector.
Goals: Heinze 44, Smith 90.
Ref: M Messias (S Yorkshire).