Fly-half Luciano Orquera kicked 10 points and Kris Burton dropped a match-winning goal as Italy belied their status as Six Nations also-rans to stun tournament co-favourites France 23-18 at the Olympic Stadium here on Sunday.
France came into their opener buoyed by three morale-boosting wins over Australia, Argentina and Samoa in November, but under pressure to make a solid start, having finished a mediocre fourth in last year's edition.
Adding to coach Philippe Saint-Andre's task was knowing that on their last outing in Italy, in March 2011, they suffered a 22-21 defeat.
With Italy showing progress in their own November test campaign, notably against New Zealand and Australia, France came to the capital ready for a physical encounter.
Instead, the hosts eschewed the errors for which they have become known and added their own brand of expansive, flowing rugby to frustrate France throughout a thrilling encounter.
"You have to says hat's off to Italy," said Saint-Andre. "They're 10th in the (world) rankings, they're improving all the time and today they simply deserved to win.
"We were lacking in terms of precision, we gave the ball away too often and didn't use the opportunities we created to pull ahead when we could have."
Italy coach Jacques Brunel was made to sweat for the remainder after Burton, a 64th minute replacement for Orquera, gave Italy a 23-18 lead in the 68th minute.
But the Azzurri, showing discipline in defence as France threatened in the final 10 minutes, held them off to secure a second consecutive Six Nations win almost a year after beating Scotland.
With the Scots up next for Italy at Murrayfield, Brunel said it will soon be time to keep the emotions in check.
"The team has made a lot of progress in recent years and today we gave a good image of our rugby, and showed we can play with character," he said.
"We've worked a lot on our team and a lot on our game and I liked a lot of what I seen today.
"But now we have to look forward. Everyone says Scotland are not a great team at the moment but they are a hard team to play against, especially at Murrayfield, and last year they gave a lot of teams problems."
Orquera set up Italy's opening try when he darted through the French defence to off-load to skipper Sergio Parisse who touched down on five minutes, and converted to put Italy 7-0 up inside seven minutes.
France replied with a scrambled Louis Picamoles try on 11 minutes, however the first of several errors that would prove costly for France came when Michalak missed the conversion.
Orquera, first with a drop goal then a penalty for offside, took Italy's lead to 13-5 inside the 19th minute.
France began to find their stride although full-back Andrea Masi did well to stop Benjamin Fall in his tracks with a fine tackle on the left byline.
Michalak reduced arrears to 13-8 with a penalty on the half hour and five minutes later France pulled level in emphatic style when Fall touched down as the Italian defence struggled to contain the power and movement of full back Yoann Huget and Wesley Fofana on the right wing.
Michalak converted to give France the lead but the visitors spurned the chance to add another five points when Fofana's off-load to the unmarked Fulgence Ouedraogo on the right went into touch.
Italy fell further behind to a superb Michalak penalty from 40 metres out shortly after the restart, although an even longer attempt from the fly-half slipped under the posts minutes later.
France also lost out when Maxime Machenaud's promising run to the tryline was kept in check.
Minutes later Italy prop Martin Castrogiovanni touched down for Italy from Orquera's superb ground pass. The conversion gave Italy a 20-18 lead and minutes later the stadium erupted when Burton sent the decisive drop goal through the posts from 25 metres.