Racing 92 grabbed the last place in the European Champions Cup quarterfinals after wearing down 14-man Stade Francais on Sunday.
Racing won 33-22 to take a spikey two-leg derby encounter 55-31 on aggregate.
They have beaten their neighbours four times this season.
"What is important for us is the qualification. We won all four matches, but we wanted to advance," said Racing coach Laurent Travers.
Racing flanker Wenceslas Lauret added: "We knew they were going to have a grudge, we knew they were going to come here to play, to attack us."
Trailing by 13 points after losing at home, Stade jumped into a 15-3 lead after 22 minutes.
Fullback Telusa Veainu scooped up a mishit kick by Racing flyhalf Finn Russell and ran 80 metres for the first try.
Winger Adrien Lapegue scored the second after Stade won the battle under a high kick.
Stade finished the first leg with 14 men, and they collected another red card after 35 minutes on Sunday.
Winger Sefa Naivalu, who had already spent 10 minutes in the sin bin for a tip tackle, received a second yellow, and an automatic red, for failing to use his arms in a last-ditch tackle to stop Racing fullback Louis Dupichot scoring in the corner.
The offence was also punished with a penalty try.
Stade fought back as Lapegue outpaced France wing Teddy Thomas to touch down. At half time the visitors led by nine in the match and trailed by only four in the tie.
"The coach's message at half-time was simple: just wake up," said Lauret.
Thomas took his revenge at the start of the second half, sending two defenders the wrong way and then trotting through the gap to score.
After Stade had a try disallowed following video review, tempers flared with a brawl involving almost every player on the field.
Racing finished with two tries in the last seven minutes, from Lauret and Thomas, again cutting inside and wrong-footing the defence.
"There is a lot of frustration. We are 4-0 against Racing 92 this season," said Lapegue. "It's annoying. But it was not only the red card."
In the quarterfinals, Racing will face Sale, who beat English rivals Bristol on Friday.
Four of the last eight are French, two Irish and two English, but on Saturday two of France's heavyweights squeezed through by a single point.
Montpellier lost the second leg away to Harlequins 33-20 but scraped home 60-59 on aggregate after England fly-half Marcus Smith missed a conversion in the dying stages.
In Belfast, France captain Antoine Dupont scored a last-gasp try, converted by international teammate Thomas Ramos, to seal a one-point aggregate win for Toulouse over 14-man Ulster.
Holders Toulouse won the second leg 30-23 and the tie 50-49 on aggregate.
They will face Munster, who overcame a 13-8 first-leg deficit to Exeter to run out 26-10 victors in Limerick.
Montpellier will play last season's losing finalists La Rochelle.
Kiwi playmaker Ihaia West notched up 16 points as La Rochelle beat Bordeaux-Begles 31-23 for a 62-36 aggregate score.
English Premiership leaders Leicester made sure of their place in the quarters with a 27-17 win at home over Clermont for a comprehensive 56-27 aggregate score.
Leicester will play four-time champions Leinster in the last eight, the Irish province crushed neighbours Connacht 56-20 and 82-41 overall.
QUARTERFINALS LINE-UP
Racing 92 (FRA) v Sale (ENG)
La Rochelle (FRA) v Montpellier (FRA)
Munster (IRL) v Toulouse (FRA)
Leicester (ENG) v Leinster (IRL)
Ties to be played weekend of May 8.