Biarritz returned to the Top 14 with a 27-15 victory over Bordeaux-Begles on Saturday in their first match in the French top flight since suffering relegation in 2014, while Racing 92 beat Parisian rivals Stade Francais.
The first match of the season in the Basque Country did not disappoint.
Biarritz were roared on by a vocal home crowd despite the club president threatening this week to move the team almost 1,000km north to Lille.
"We are very satisfied. We wanted a quick start and to try to show that we can be competitive -- I hope we've done that," said sporting director Matthew Clarkin.
"I saw the intensity and the desire in this game."
Biarritz have a storied history, winning the last of their five French titles in 2006 and reaching the European Cup final in 2006 and 2010.
They suffered play-off defeats twice before finally winning promotion back to the Top 14 last season with a dramatic penalty shoot-out win over local rivals Bayonne.
But Biarritz have the smallest budget in the division this term and president Jean-Baptiste Aldige said that he may move the club due to a lack of support from the local government.
"We're escaping because we've (been) given a death sentence here," Aldige told AFP on Thursday.
But the players did not look distracted, as English fly-half Brett Herron kicked an early penalty before crossing to score their first try.
Three points from the boot of France star Matthieu Jalibert were all Bordeaux could muster in the first period as they trailed 17-3 at half-time.
Hooker Lucas Peyresblanques had touched down for Biarritz's second try before the break, and Romain Lonca scored in the 45th minute to put the game beyond Bordeaux's reach.
Herron kicked a penalty in the 52nd minute to extend the lead to 27-3 and take his points tally for the match to 17.
Bordeaux managed two late consolation tries through Alban Roussel and Yoram Moefana.
- Racing start strongly -
Racing eased past their city rivals Stade Francais 36-21 at the Stade Jean-Bouin.
Stade centre Gael Fickou started against his former club after his controversial mid-season switch earlier this year.
"The guys opposite, they are my friends and I still see them away from the pitch so it's never easy," said Fickou, who was jeered by the home fans.
"But when you enter the field, you are there to fight against the opponent.
"Today I am part of Racing and I am fighting 200 percent for my team. I hear them (the boos) but I ignore them. I understand them too."
But it was Camille Chat and Donovan Taofifenua, a cousin of France internationals Romain Taofifenua and Sebastien Taofifenua, who crossed the tryline as Racing took a 20-6 advantage at the interval.
The dominant first-half performance brought back memories of last season's play-off first round, when Racing led 28-0 at the break before winning 38-21.
This match continued to follow a similar pattern, as Sefa Naivalu's try for Stade was quickly followed by Olivier Klemenczak restoring Racing's lead.
France scrum-half Maxime Machenaud kicked 13 points in total as Racing always stayed in control, with Kylan Hamdaoui's 79th-minute score for Stade barely taking the shine off the visitors' victory.
Elsewhere on the opening day, Enzo Herve scored 26 points as Brive thrashed promoted Perpignan 36-15, while Castres edged Pau 16-12.
Montpellier visit Toulon later on Saturday.