France held off a spirited late challenge from a Diego Dominguez-inspired Italy to win their Six Nations Championship clash 30-19 at the Stadio Flaminio.
The French had led just 14-9 at the interval but stretched that lead to 23-12 before Dominguez put Italy back into the game, converting a try by Massimiliano Perziano.
That set up a frantic finale, but in a tense finish Sebastien Bonetti scored a last-gasp converted try to ensure a healthy margin of victory for the French.
The 100 per cent accuracy of Dominguez's goalkicking was in contrast to opposite number Christophe Lamaison, who landed six from 11, but France were just too strong for their Latin neighbours.
Dominguez put the first points on the board with a penalty after 11 minutes but just three minutes later France took the lead with their first attack of the match.
There was a hint of fortune in the score as fly-half Lamaison's grubber kick bounced up perfectly for onrushing full-back Jean-Luc Sadourny, who eluded opposite number Christian Stoica to score behind the posts, making the conversion a formality for Lamaison.
But Dominguez pulled back the score to 7-6 with another penalty while Lamaison missed from a similar position a minute later.
After 25 minutes France stretched their lead with a fine try that started in their own half.
Lamaison and Sadourny combined to create another opening and the full-back slipped the ball to wing Philippe Bernat-Salles, who touched down with Lamaison again being left a simple conversion.
Another Dominguez penalty put Italy back within touch at 14-9 and with half-time looming Lamaison missed another.
Johnstone kept Italy on the field at half-time, giving his pep-talk in full public view as he sought to keep his troops from repeating the second-half collapse that occurred in their matches against Ireland (22-41) and England (23-80).
The second half opened with Italy producing a spell of sustained pressure and twice declining kicks at goal in vain bids for tries, but paid when Lamaison launched a counter-attack and notched the resultant penalty.
Dominguez immediately hit back with the help of a penalty to make it 17-12 to France, although the scoreboard operator had somehow come up with a score of 47-9 in favour of the visitors. Eventually the scoreboard was switched off.
Lamaison squandered another penalty but almost immediately was handed another and this time he made no mistake.
France thought they had the match tied up when flanker Olivier Magne appeared to touch down but English referee Chris Whyte decided an infringement had been committed.
But another penalty from Lamaison gave France a 23-12 lead with only 17 minutes remaining.
Italy were visibly wilting and New Zealander Johnstone introduced Juan Manuel Queirolo for scrum-half Alessandro Troncon. The mistakes kept coming though and Lamaison missed another opportunity for France.
But out of the blue Italy pulled themselves into the match when Dominguez linked up with Denis Dallan, who kicked through and Massimiliano Perziano won the race to touch down.
Dominguez converted and now the score was 23-19. But Bonetti's late effort, converted by Lamaison, settled the issue.