Manchester United hit back from a goal down to see off Benfica and ensure qualification for the Champions League knockout stages as Group F winners.
Wayne Rooney leads the celebrations after Vidic's opener
Benfica went ahead midway through the first half when defender Marcos Nelson drilled in a stunner from 25 yards.
But that only prompted a rousing response from United and Nemanja Vidic drew them level with a fine header.
Ryan Giggs further eased the nerves with another precise header, before Louis Saha wrapped it up from 12 yards.
The night turned out to be a comfortable one for United, but the home fans will wonder why it took until Nelson's strike for them to play with the sort of tempo that went on to cause Benfica all sorts of problems.
A conservative 4-5-1 formation at kick-off suggested United lacked urgency, and Nelson's fierce strike confirmed the supporters' worst fears.
In fairness, United's response was immediate, Cristiano Ronaldo seeing his drilled free-kick punched away before Saha's header from the resultant corner was cleared off the line.
From then until the end of the half, with Wayne Rooney pushed back up front in a 4-4-2 formation, United laid siege to the Benfica goal.
Rio Ferdinand and then Paul Scholes came close to drawing United level, but a brave block from Luisao and another fine Quim save protected Benfica's lead.
Despite the increased tempo, the Old Trafford faithful were becoming audibly frustrated, but a minute into first-half stoppage time they roared their relief as United deservedly drew level, Vidic rising unmarked to head into the net from Giggs' free-kick.
United refused to let up in the second half and it soon reaped its rewards as they took the lead.
Giggs' precise header eased United's nerves
Ronaldo, who moments earlier had seen his penalty appeal waved away correctly after he had fallen theatrically in the box, sent in a pinpoint cross that Giggs headed home with equal precision.
The goal extended Giggs' run to 12 consecutive seasons scoring in Europe's premier competition and, despite a couple of impressive solo runs from Simao, the fight appeared to have gone out of Benfica.
And so it proved on 74 minutes when Saha thumped home a header from Rooney's corner.
With half an eye on Saturday's derby match against Manchester City, Sir Alex Ferguson took the chance to take off Giggs and Scholes and the veteran pair walked off to a standing ovation.
In truth, as soon as Vidic equalised the victory had rarely looked in doubt and the hosts went on to comfortably gain revenge over the side that had dumped them out of the competition at this stage last season.
Man Utd: Van der Sar, Neville, Ferdinand, Vidic, Evra (Heinze 67), Ronaldo, Carrick, Scholes (Solskjaer 78), Giggs (Fletcher 73), Saha, Rooney.
Subs Not Used: Kuszczak, Brown, O'Shea, Silvestre.
Booked: Rooney, Fletcher.
Goals: Vidic 45, Giggs 61, Saha 75.
Benfica: Quim, Nelson, Luisao, Ricardo Rocha, Leo, Katsouranis, Petit, Simao, Nuno Assis (Karagounis 73), Miccoli (Paulo Jorge 63), Nuno Gomes.
Subs Not Used: Moretto, Anderson, Mantorras, Miguelito, Beto.
Booked: Ricardo Rocha.
Goals: Nelson 27.
Ref: Herbert Fandel (Germany).