Paris (AFP) - Monaco gave themselves a massive boost ahead of their Champions League clash at home against Arsenal with a convincing 3-0 victory over nine-men Bastia in Ligue 1 on Friday as Guingamp won 2-1 at Nice. The Principality side, who have a game in hand, are sitting fourth three points behind third-place Marseille, who take on leaders Lyon on Sunday in the Stade Velodrome.An Anthony Martial double along with a first-half goal from Brazilian Matheus Carvalho went a long way to consoling Leonardo Jardim's side who were dumped out of the League Cup by the Corsicans last month.Bastia fell apart, showing early signs of fatigue after being reduced to nine-men when Drissa Diakite and Giovanni Sio saw red on both sides of the break."It was the perfect evening," said Jardim."We needed to win to prepare for Arsenal.