Ndjantou scored his first goal for the club while Mbaye managed two assists, with Portuguese forward Goncalo Ramos and substitute Desire Doue adding the other goals for PSG.

Four days before PSG play the Intercontinental Cup final against Brazil's Flamengo in Qatar, coach Luis Enrique rested a host of players for the trip to northeast France.

Even though Ballon d'Or winner Ousmane Dembele was not deemed well enough to play after an illness, Luis Enrique left Doue, Bradley Barcola, Joao Neves, Khvicha Kvaratskhelia and goalkeeper Lucas Chevalier on the bench.

Instead, 17-year-old Mbaye and 18-year-old Ndjantou were picked either side of Ramos in attack, and they did not disappoint.

After a quiet opening, the game burst into life in the final 15 minutes of the first half.

Ramos gave PSG the lead when he headed home a cross from Lee Kang-in on 31 minutes.

On 39 minutes Ndjantou slid home Mbaye's devilish cross into the six-yard box.

Just three minutes later, Jessy Deminguet lashed home for Metz from outside the area after a ricochet fell into his path.

Danish goalkeeper Jonathan Fischer denied Ramos with a smart save to keep Metz in the game after the break.

Habib Diallo had a chance to equalise just before the hour mark but shinned his volley from the edge of the box wide of the upright.

Doue seemed to have sealed the victory for PSG when he raced clear from his own half, released by Mbaye, as Metz were caught pushing up at a corner.

Doue ran 70 yards before calmly slotting past Fischer.

A week after scoring his first goal of the season against Rennes, Mbaye hit the woodwork on 71 minutes.

Georgiy Tsitaishvili gave Metz hope nine minutes from time with a  curling effort from outside the box, but PSG held on.

Lens can return to the Ligue 1 summit if they beat Nice -- who have lost eight straight games in all competitions -- on Sunday.

Earlier in the day, Rennes moved up to fifth with a 3-1 come-from-behind victory over Brest.