However at the start of the 2006–07 season, Mensah was sidelined with a calf injury that saw him out for a month. It was not until on 9 September 2006 when he made his first appearance of the season, starting the whole game, in a 2–1 win against Sochaux. Since making his return from injury, Mensah's performance led the club's website published an article on Mensah's impact on his new team. It said, "The summary from 11 February 2006 to 28 September 2006: 18 games: 12 wins, 5 draws, 1 defeat. 12 conceded goals, 4 of them when Mensah was not on the field. Rennes conceded 0.66 goals per game with Mensah. Without Mensah Rennes had 6 games, 0 wins, 1 draw and five losses. 13 goals were conceded, making 2.66 per game." He then regained his first team place for the next seven matches before being sidelined with an injury that kept him out for two months. In November 2006, Mensah was rated the number 1 player in France"France Football" magazine, level with Juninho, in the 2006–07 season's "Top 100 French League players". It was not until on 14 January 2007 when Mensah returned to the starting line–up, in a 2–0 loss against Marseille. He then followed up with the next three matches by keeping three consecutive clean sheets between 24 January 2007 and 3 February 2007. After being sidelined on two more occasions later in the 2006–07 season, Mensah continued to regain his first team place, playing in the centre–back position. At the end of the 2006–07 season, he went on to make twenty–five appearances in all competitions. For his performance, Mensah finished second place behind Mario Melchiot for the club's best player of the year. Following this, it was announced on 17 May 2007 that Mensah signed a contract extension with Rennes, lasting until 2010. "I am very lucky to be able to stay one year more with such an ambitious club, especially since a lot of clubs wanted me", Mensah told "L'Équipe". Rennes head coach Pierre Dréossi said, "Those who wanted to see him at another club can now forget my telephone number."