(Adds Blanc quotes)
By Gregory Blachier
PARIS, Jan 31 (Reuters) - Zlatan Ibrahimovic and Alex scored second-half goals as Paris St Germain marked Yohan Cabaye's debut with a 2-0 win over Girondins Bordeaux on Friday that opened a six-point gap at the top of Ligue 1.
Brazilian Lucas Moura set up both goals. The league's top scorer Ibrahimovic netted his 18th of the season after 58 minutes before Brazil defender Alex produced a deft half-volley two minutes from time.
PSG have 54 points from 23 games, six ahead of second-placed Monaco who visit mid-table Lorient on Saturday.
France midfielder Cabaye, the club's midweek signing from Newcastle United, came on as a substitute and hit the post with a header.
The evening started with the fans cheering Cabaye but PSG were booed at the break after failing to create any clear-cut chances.
The hosts eventually went ahead when Sweden forward Ibrahimovic tapped the ball into the net from close range following Moura's precise low cross from the right.
Cabaye, 28, replaced Javier Pastore late on and almost netted from an Ezequiel Lavezzi centre.
"I have no worries for Yohan. He's a smart lad, he knows how we want to play and will easily adapt," coach Laurent Blanc told a news conference.
PSG wrapped up victory when Alex popped up in the area to turn Moura's corner into the net.
"With his pace and technique you give Lucas the ball and he sets up some incredible things," Blanc said.
The only worry for PSG, who meet Bayer Leverkusen in the Champions League last 16 next month, came when striker Edinson Cavani left the field in the second half with a thigh problem. (Reporting by Gregory Blachier; Editing by Ken Ferris)