Neymar regularly made himself available and his neat passing in small spaces gave PSG several chances, his relationship with Cavani looking particularly promising.
Neymar's long awaited debut for Paris Saint-Germain on Sunday evening did not disappoint.
The Brazilian was handed a start on his first appearance since a world-record 222 million-euro ($261 million) transfer from Barcelona.
Edinson Cavani scored the second goal for PSG in the 62nd minutes after being superbly set up by Neymar and he wasted no time to fired in far corner of the net.
It was an all round decent debut for the world's most expensive player and this goal against Guingamp created history.
Nationals Bryce Harper carried off field with apparent knee injury
With the rainout on Friday and the Giants not returning to Washington D.C.in 2017, Saturday's game was a must for the two teams. The San Francisco Giants hand the ball to right hander Jeff Samardzija for Sunday's start at the Washington Nationals.
Neymar drove one shot over the crossbar but Marquinhos came the closest to breaking the first-half deadlock after his bullet header cannoned back off the crossbar.
PSG eventually took the lead in the 52nd minute as Guingamp defender, Jordan Ikoko turned the ball into his own net, 0-1.
Neymar celebrates with Cavani.
Nine days on from Mbappe limping off in the 3-2 victory over Toulouse, and amid considerable speculation linking him with a move to PSG, the 18-year-old was named as a substitute for this contest by boss Leonardo Jardim. Earlier, Lille were beaten 3-0 at promoted RC Strasbourg, conceding all three goals after striker Nicolas de Préville took over as goalkeeper following the sending off of Mike Maignan in the 63rd minute.