Two late goals left us down and out after a decent performance at Old Trafford.
We enjoyed plenty of possession but, in truth, didn't really hurt a United defence that has been under the spotlight of late.
The difference was in the final third. United created the better chances but, with Ruud Van Nistelrooy having a rare off day against us, did little with them until Ronaldo and David Bellion left Sir Alex Ferguson's men celebrating a somewhat flattering final scoreline.
Positive points for us included the performance of Dean Marney in his first start, another fine display in midfield from Ledley King and another half-hour for Jamie Redknapp off the bench.
With a swirling wind around the stadium making any cohesive football a test, the first half was an even affair with the home side just about holding the upper hand.
Christian Ziege, King and Michael Brown all had decent efforts on goal - Ziege headed Steve Carr's cross wide, Brown's shot deflected just over - but United might have done better via Van Nistelrooy and Diego Forlan.
The best chance fell to Van Nistelrooy on 18 minutes, latching onto Giggs' pass and nipping around Kasey Keller only for Gary Doherty to save the day with a superb block.
Forlan hit the side-netting and Van Nistelrooy uncharacteristically failed to get the ball under control when O'Shea's pass released set him clear and Taricco was able to shut out the danger.
Giggs struck a minute after that chance on the half-hour. The ball was worked down the right flank, Ole Solskjaer crossed low and Giggs back-heeled home from six yards.
We hit back though, Marney drove wide after good work from Defoe and Carr's 30-yarder forced Carroll into a scrambling save to his right.
Defoe then looked to get onto a pass from Keane only for Brown to hack him down - it looked like a foul, although the ball was going away from the striker. Nothing given.
Stephane Dalmat came on for Mauricio Taricco at half-time to add a more offensive slant to the line-up but United might well have added to their lead in the opening exchanges.
Forlan failed to control in front of goal from Roy Keane's cross and Keller was at his best to palm away Giggs' effort from six yards.
Our best spell followed but, again, no chances apart from Carroll's fine save to keep out Brown's 20-yarder after 67 minutes.
It remained even but Giggs and Van Nistelrooy both went close for United before Keller's fingertips diverted Forlan's dipper.
The game was put beyond doubt by Ronaldo a minute from time, a low shot in off the post and then a harsh third goal as David Bellion, another substitute, cut in from the left before shooting home.
MINUTE BY MINUTE GUIDE
7mins: After even start, Van Nistelrooy lashed in first shot, dipping volley just over from 22 yards.
10mins: Good movement between Keane and Defoe, Carr's deep cross headed wide by Ziege.
13mins: Scholes nipped in front of Brown, left side of area, early shot across Keller flew a couple of yards wide.
17mins: Great tackle from Brown on Scholes won ball for King, 30-yarder always drifting wide.
18mins: SAVING TACKLE. Giggs on the break, fed Van Nistelrooy who went past Keller only for Doherty to block his tap in.
20mins: CLOSE. Brown shot took slightest of deflections, sailed just over.
22mins: CLOSE. Good hold up play from Solskjaer under pressure from Taricco, rolled ball to supporting Forlan who hit side netting from 18 yards.
29mins: CHANCE. Van Nistelrooy onto O'Shea pass, through on Keller, didn't really get ball under control and Taricco excellent cover to shut out chance.
30mins: GOAL. Low cross from Solskjaer, right-hand side, back-heeled home by Giggs from six yards. 0-1.
39mins: Good feet and pace from Defoe to get away from two challenges, Giggs foul just as he passed to Marney not given, Marney first-time shot wide.
43mins: Carr 30-yarder forced Carroll into scrambling save to his right.
Half-time: United 1, Spurs 0
Half-time: SUB. Dalmat for Taricco.
52mins: CHANCE. Keane drive to byline, stood up perfect cross that cut out Keller but Forlan, free at far post, failed to control.
56mins: SAVE. Giggs through King's tackle, only six yards out, low shot parried by Keller.
58mins: YELLOW. Giggs for shirt pull on Dalmat.
60mins: SAVE. Brown drilled in shot from edge of box gathered low to his left by Carroll.
67mins: SUB. Redknapp for Marney.
71mins: CLOSE. O'Shea one-two with Keane, fired in cross from byline, first time shot from Giggs whistled just over.
73mins: Van Nistelrooy side foot just wide as United overdid it in box.
74mins: YELLOW. Carr for foul on Van Nistelrooy.
76mins: Dalmat shot wide from 25 yards.
76mins: SUB. Ronaldo for Solskjaer.
80mins: SAVE. Keller fine tip over from Forlan's dipping, curling effort from 25 yards.
81mins: SUB. Kanoute for Defoe.
83mins: SUB. Butt for Forlan.
89mins: GOAL. Ronaldo low 25-yarder in off the post. 0-2.
Injury time: SUB. Bellion for Scholes.
Injury time: GOAL. Bellion cut in from left, drilled home from 15 yards. 0-3.
Line-ups: Manchester United: Carroll, P Neville, Brown, O'Shea, Silvestre, Van Nistelrooy, Giggs, Scholes (Bellion, 90), Keane, Solskjaer (Ronaldo, 76), Forlan (Butt, 83). Subs: Howard, Fletcher.
Spurs: Keller, Carr, Taricco (Dalmat, 45), Gardner, Doherty, King, Brown, Marney (Redknapp, 67), Ziege, Keane, Defoe (Kanoute, 81). Subs: Hirschfeld, Kelly.
Referee: Dermot Gallagher.