Downing (right) sprints to victory ahead of Michael Albasini (left) and Fedrigo (centre)
British duo Russell Downing and David Millar won a stage apiece on the final day of the Criterium International.
Team Sky's Downing, 31, outsprinted the field at the end of a 75km second stage on the island of Corsica while Garmin's Millar won the 7.7km time trial.
France's Pierrick Fedrigo won the two-day, three-stage race.
Seven-time Tour de France winner Lance Armstrong and 2009 champion Alberto Contador finished well down in their first meeting since last year's Tour.
Pre-race favourite Contador finished second in the time trial, two seconds behind Millar, to move up to 15th overall, while Armstrong was 47th, more than five minutes down on Fedrigo.
"We knew Lance would not be at his best physically at this stage of the season
RadioShack team manager Johan Bruyneel
Millar completed the third and final stage in nine minutes, 50 seconds to catapult the Scot up to joint fourth, 19 seconds behind the winner.
The national 2007 road race and time trial winner said: "It felt really good. I really enjoyed it.
"I rode like a bat out of hell, and didn't think about it. I just ran hard."
Fedrigo won Saturday's opening hilly stage before sprinting to third place behind Downing in the first of Sunday's two stages.
And his time trial of 10:06 was enough to see him take the title by 14 seconds from Australia's Michael Rogers with Portugal's Tiago Machado third.
Johan Bruyneel believes Armstrong has a lot of work to do
"It's not like winning the Tour for the Tour is another dimension," said Fedrigo.
"But the Criterium is the biggest race so far this season in terms of the quality of the field and I'm proud.
"I now want to go even higher and do well in the Ardennes classics."
Downing, the 2005 British road race champion, had set his sights on Sunday's sprint because he knew he had no chance in the hills.
"I came to the Criterium to win the sprinters stage, so I'm happy," said Downing after his 18th career stage win.
Team Sky worked with HTC-Columbia at the front of the peloton to reel in a breakaway of six riders with around five kilometres remaining before setting up a lead-train for the sprint finish.
Downing, from Rotherham, clocked one hour, 42 minutes, 20 seconds to finish ahead of Armstrong, Contador and world champion Cadel Evans of Australia, who all had the same time.
"The boys were working for me so that was good," Downing added.
"In the last kilometre, I started to go into the HTC-Columbia train. I went to look out but it was hard because of the wind, so I went down a gear."
Meanwhile, RadioShack team manager Johan Bruyneel has questioned Armstrong's preparations for the race.
After sitting out last weekend's Milan-San Remo classic, Armstrong flew to Paris to meet French President Nicolas Sarkozy and dropped in on former Tour winner Laurent Fignon before flying to southern France where he owns a house.
Bruyneel, who helped the American win his seven Tours de France, conceded: "We knew he would not be at his best physically at this stage of the season."
"He always trains by himself but what you need is to take part in stage races.
"You need to wake up every morning at the same time, eat (at the same time), recuperate, it's routine.
"There will be more training in the mountains and there is still a lot of time (before the Tour de France) but there is still a lot of work to be done."