Bastareaud, 21, was making his first Test start since disgracing himself on his country’s recent tour of New Zealand when he falsely claimed he had been assaulted when he had actually drunkenly fallen over a table.
But Stade Francais star Bastareaud, a cousin of Arsenal football star William Gallas, repaid the faith of coach Marc Lievremont with a man-of-the-match performance and a two-try salvo to get the pre-tournament favourites off to the perfect start.
“We are very happy, obviously,” Lievremont said of Bastareaud’s display. “We were happy for his performance but also the team performance.”
But he refused to let his match-winner take all of the credit, adding: “Mathieu was just like any other player today. The management certainly did not put any extra pressure on him.”
Morgan Parra kicked over two penalties and a conversion for Les Bleus, although last-ditch tackles from Thom Evans and Sean Lamont saved the Scots from a heavier defeat.
Chris Paterson landed three penalties for the hosts, but, in truth, Andy Robinson’s men looked powder-puff in attack.
Former England coach Robinson added: “The most significant difference was in that first half, the two chances that they had, they took beautifully. “We needed to control the scoreboard in this game but we were unable to do that through turning over possession in our half during that first 30 minutes.”