Substitute David Bellion grabbed an injury-time equaliser to save Manchester United's blushes, just as Bolton Wanderers looked set to claim their first win at the Reebok Stadium over United in the Premiership.
After new signing Gabriel Heinze had given United a 44th minute lead, Wanderers equalised through Kevin Nolan, then Les Ferdinand came on to score in the 89th minute after United keeper Tim Howard had been involved in a mix-up with Mikael Silvestre.
Then with two minutes of added time signalled, Ronaldo knocked Ryan Giggs' corner into the six-yard area. Several Bolton defenders and goalkeeper Jussi Jaaskelainen seemed to leave the ball to one another and in the end it trickled over the line with Bellion appearing to get the final touch.
Wanderers started the game without two of their international stars, Stelios and Ricardo Gardener, but for United it was a mounting injury list that forced Sir Alex Ferguson to bring back two key players.
It was thought that Ruud van Nistelrooy would have eased his way back into action following his hernia operation via the substitutes bench, but Ferguson threw him straight in for his first competitive game in ten weeks to partner Alan Smith.
And with John O'Shea missing through injury, Wes Brown made a welcome return to the heart of the defence for his first game of the season.
Gary Neville was also missing after picking up an injury while on England duty, leaving the way open for brother Phil to deputise at right-back.
Wanderers brought in Kevin Nolan to replace Stelios in midfield and Anthony Barness replaced Gardener who made a late return from World Cup action with Jamaica.
United also brought in full-back Heinze for his debut and the Argentinian quickly adapted to Premiership life as his side made a promising start.
The Wanderers defence had the busier time of it in the first quarter of an hour, United using the wing talents of Giggs and Kleberson to good effect.
Wanderers managed to hold firm, but they were almost undone in the 15th minute when Smith was given time to shoot at goal but straight at Jaaskelainen.
Bolton could also have got on to the scoresheet in the first half-hour as Nolan played a teasing cross into the goalmouth, but Kevin Davies was unable to get the touch.
Then when the United defence struggled to clear a similar move Nicky Hunt picked up the ball, but only succeeded in firing high over the bar.
Yet it was Silvestre who should have claimed the game's first score when he found himself clear 12 yards out.
He hit the ball well, but Jaaskelainen was quickly off his line to clear with his feet and Kleberson fired the rebound wide.
The game was being spoiled by some niggling fouls and it was no real surprise when the first yellow card was shown on 38 minutes, when Jay-Jay Okocha was penalised for bringing down Roy Keane.
Van Nistelrooy then showed his first real goal threat with a 40th minute header that forced a good save from Jaaskelainen.
Yet when he won a corner three minutes later it gave United the chance to go in front.
Giggs' corner was met at the far post by Silvestre, who headed it back into the goalmouth where Heinze fired the ball into the net.
Wanderers' reaction was to replace Henrik Pedersen with El Hadji Diouf at the start of the second half.
And the Senegal international, currently on a 12-month loan spell from Liverpool, was indirectly involved in earning Wanderers an equaliser in the 51st minute.
It came about after he won a free-kick at the expense of Phil Neville. The ball was then played to Okocha whose shot hit Howard, but Nolan was on hand to head in the rebound.
Davies was then only inches away from giving Wanderers the lead with a shot that whistled past the far post, before Brown was on the spot to deflect an Okocha goalbound shot to safety.
A United substitute then almost gave them back their lead when Ronaldo replaced Kleberson. He tricked his way from the touchline to the edge of the area before firing in a tremendous shot that beat Jaaskelainen only to crash against the bar.
In a rousing finish Diouf flashed a shot past the post, then Ferdinand was on hand to grab what looked to be the winner, only for Bellion to equalise two minutes into added time.