New-look Bordeaux off to winning start in France
Gaetan Laborde, Uruguayan international Diego Rolan and Brazilian youngster Malcom all netted for the hosts at the Matmut Atlantique but they were made to sweat as Romain Hamouma and Alexander Soderlund both scored late goals for the visitors.
Saturday's game was the competitive bow for Gourvennec, appointed as Bordeaux's new coach to end a successful six-year stint in charge of unfashionable Brittany side Guingamp.
There was no place for either of his marquee summer signings in the starting line-up, with former Monaco midfielder Jeremy Toulalan suspended and forward Jeremy Menez only on the bench.
However, young forward Laborde, who has spent most of the last two seasons on loan in the second tier, opened the scoring 13 minutes in when he got in front of Loic Perrin to head in a free-kick.
Saint-Etienne goalkeeper Stephane Ruffier kept the visitors in the game with a fine save from Malcom before Nicolas Pallois had a header cleared off the line as it remained 1-0 at the interval.
However, Laborde set up Rolan to make it 2-0 early in the second period and Malcom, the 19-year-old signed in January from Corinthians, curled in a free-kick for the third goal.
Saint-Etienne rallied, though, and Hamouma headed in nine minutes from time before Norwegian striker Soderlund, who had come off the bench, got to a corner in front of goalkeeper Jerome Prior to make it 3-2.
Bordeaux, who saw Menez come off the bench to make his debut wearing a headguard to protect the ear he had partially ripped off in a gruesome pre-season friendly incident, held on as Vincent Pajot grazed the post with a shot in stoppage time.
"We managed to score three goals. There were things that were not perfect, but for a first match that is inevitable. It is difficult to control everything," said Gourvennec.
- Eder jeered -
There were plenty of goals elsewhere, with promoted Metz coming from behind twice to beat Lille 3-2.
Portugal's Euro 2016 final hero Eder started for Lille and was jeered by the home support at the Stade Saint-Symphorien but it was another Portuguese player, Rony Lopes, who scored both goals for the visitors.
However, Mevlut Erding netted twice for the hosts, his second from the spot, before a Yann Jouffre spot-kick secured the win late on.
Caen came from two goals behind to beat 10-man Lorient 3-2 as Croatian summer signing Ivan Santini marked his debut with a brace.
Cameroon forward Benjamin Moukandjo had scored twice for Lorient but they then had Zargo Toure sent off and Ronny Rodelin pulled one back before Santini's double.
Nantes won 1-0 at Dijon with a Nicolaj Thomsen goal and a Ryad Boudebouz goal was enough for Montpellier to beat Angers.
On Friday champions Paris Saint-Germain began their quest for a fifth consecutive title by winning 1-0 at Bastia, Layvin Kurzawa scoring the only goal in Corsica.
Monaco warmed up for their trip to Villarreal in the first leg of their Champions League play-off next midweek by coming from two goals down to draw 2-2 with Guingamp, Bernardo Silva grabbing the late equaliser.
Last season's runners-up Lyon begin their campaign at promoted Nancy on Sunday, while Nice host Rennes and Marseille are at home to Toulouse.