Giroud scored twice, as France registered a comfortable 5-2 victory over Iceland at Stade de France in Saint-Denis on Sunday night.
Former United winger Giggs was impressed with the performance of the Arsenal striker.
“I mean, he can hold the ball up, he scores goals, obviously physically he is very strong, but yeah he can be frustrating at times. But to be fair to him, in this tournament he has pitched in with a lot of important goals.”
Against Iceland, Giroud scored two goals, had a pass accuracy of 65%, created one chance, and won 75% of his tackles and 80% of his headers.
In four matches for France at the 2016 European Championship so far, the Arsenal striker has scored three goals and created six chances.
During the 2015-16 season, the 29-year-old scored 16 goals and created 36 chances in 38 Premier League matches for Arsenal.
Giroud scored five goals and created five chances in seven Champions League matches for the Gunners in 2015-16.
France will take on Germany in the quarter-finals of Euro 2016 at Stade Velodrome in Marseille on Thursday evening.
Portugal and Wales will face each other in the other quarter-final tie at Parc Olympique Lyonnais in Lyon on Wednesday evening.