PARIS : Paris St Germain forward Kylian Mbappe scored twice to help the Ligue 1 leaders beat Metz 3-1 at the Parc des Princes on Wednesday and close out the year on a high as they maintained their five-point advantage at the top of the table.Vitinha put the hosts in front early into the second half, scoring with his first touch, before Mbappe doubled the lead on the hour mark with a stunning shot from the edge of the box as the France forward celebrated his 25th birthday.Metz captain Matthieu Udol pulled one back with a towering header following a corner, as the ball went in off the inside of the post, before Mbappe made it 3-1 profiting on a mistake from the visitors' defence.PSG, who sit top of the standings on 40 points from 17 games, are five points ahead of second-placed Nice and seven points above AS Monaco, in third.