Metz have registered their first away win of the season thanks to a first-half goal from Gaetan Bussman.
After the visitors had threatened with a couple of half-chances, Guingamp's Claudio Beauvue just cleared the crossbar from 25 yards as his side tried to move clear of the relegation zone.
However, their quest was made tougher midway through the first half when Bussman drove a left-footed strike into the top corner from inside the penalty area following a corner from Yeni N'Gbakoto.
Florent Malouda had an opportunity to make it 2-0 before the break but the former Chelsea midfielder's shot from 20 yards was comfortably saved by Mamadou Samassa.
Guingamp came out firing at the beginning of the second half with two openings through Beauvue and a Jeremy Pied strike threatening the Metz goal in the opening five minutes after the restart.
Metz replied with two chances of their own from Malouda and Sergei Krivets but they were unable to double their advantage to discourage their opponents.
The home side pushed for an equaliser in the final quarter of the match, with the best opening falling to Rachid Alioui who had a header kept out by Anthony Mfa Mezui, who flung himself to his right.
Despite seeing out the match to record their third success of the campaign, the contest ended on a sour note for Metz, who had N'Gbakoto dismissed for a second bookable offence.
