(Makes clear Moutinho, Martial were replaced)
PARIS, March 1 (Reuters) - Monaco suffered their first defeat of they year when they lost 2-0 at European hopefuls St Etienne on Saturday, leaving Ligue 1 leaders Paris St Germain five points clear at the top of the table with a game in hand.
Midfielder Fabien Lemoine opened the scoring on 17 minutes with a stunning half-volley and Romain Hamouma netted the second in the 67th for St Etienne, who climbed up to the third Champions League qualifying spot.
Monaco, who were unbeaten in all competitions this year, have 56 points from 27 games, with St Etienne eight points behind them.
Champions PSG, who are chasing the first back-to-back titles in their history, can open an eight-point lead if beat fifth-placed Olympique Marseille at home on Sunday.
St Etienne, who have now won six of their last seven home games, made a strong start on a poor pitch and midfielder Lemoine narrowly missed the target with a half-volley following a corner kick in the 14th minute.
A similar situation saw him put the hosts in front from 25 metres three minutes later.
Monaco failed to threaten the home goalkeeper Stephane Ruffier until six minutes before halftime when Lemoine cleared a close-range effort from centre back Nicolas Isimat-Mirin, who was covering for Eric Abidal's absence through illness.
The visitors continued to labour in the second half despite substituting Joao Moutinho and Anthony Martial with wingers.
St Etienne doubled their lead when striker Hamouma ran at goal from his own half, skipped past four opponents and was helped by goalkeeper Danijel Subasic who failed to hold the shot and the ball bounced off his hand into the net.
(Reporting by Gregory Blachier; Editing by Rex Gowar)