PSG seal French Cup final spot against minnows Les Herbiers

Paris Saint-Germain's Kylian Mbappe (left) outruns Caen's Stef Peeters during the French Cup semi-final football match. (CHARLY TRIBALLEAU/AFP)

PSG travelled to the Normandy coast with the French league title already wrapped up and looking to take another step towards what would be a fourth consecutive Cup triumph - a record - if they beat third division Les Herbiers at the Stade de France on May 8.

But while dominant throughout, Unai Emery's men were kept on their toes in an at times messy encounter in which they had one goal chalked off by the Video Assistant Referee (VAR), and Mbappe's second fall under its scrutiny before it was confirmed nine minutes from time.

PSG should have opened the scoring early but Angel Di Maria saw a weak rolled shot collected by 'keeper Brice Samba on 17 minutes.

But despite poor pitch conditions, the French champions were quickly into their stride with Mbappe, outstanding on the night, opening the scoring on 21 minutes.

A textbook move from midfield saw Edinson Cavani in possession to the left of the area.

When the Uruguayan striker rolled across the area, Samba misjudged his lunge to leave Mbappe with an easy tap in from yards out.

PSG were firmly in control against a Caen side reeling from four consecutive league defeats.

But Patrice Garande's men pounced to level shortly before the half-time interval.

PSG's defence stepped back amid a Caen offensive and when a deflected shot fell to Ismael Diomande his shot deflected off Adrien Rabiot to leave Kevin Trapp snatching for thin air.

PSG replied moments after the second half began after a defensive blunder by Damien Da Silva saw Cavani add his name to the scoresheet.

It was ruled out for offside, Di Maria the culprit.

But with the clock ticking down, Caen's hopes of taking the tie into extra-time were dashed by yet another textbook move that saw PSG restore their lead.

Again, VAR was used to check whether Cavani was offside when he ran on to a slick backheel by Di Maria and rolled across the area for Mbappe to fire past Samba nine minutes from time.

This time, the goal stood. PSG added a third in the final minute of added-on time after Nkunku completed a great one-two to run through and leave Samba with no chance.