Nabil Bentaleb scored four minutes into his first appearance since suffering a heart attack to inspire Lille to a 2-0 victory at Rennes Sunday with his coach hailing the player's "incredible story".
The win allowed Lille to reclaim fifth place in Ligue 1 that Lyon had briefly grabbed earlier in the day by thrashing last-placed Montpellier.
Nice won 3-1 at struggling Le Havre to climb back into the top three.
Bentaleb, a 30-year old Algerian international midfielder, suffered a heart attack last June.
He has since been fitted with a defibrillator, club sources told Agence France Presse.
The French Football Federation medical commission Wednesday cleared him to play.
He returned to the pitch after 76 minutes Sunday night, four minutes after the hosts had been reduced to 10 men when Christopher Wooh was sent off.
Lille had bombarded Brice Samba in the Rennes goal, who had also saved a weak first half penalty by Chuba Akpom.
But four minutes after coming on Bentaleb broke the deadlock, running in at the far post to poke home the rebound after another Samba save.
Bentaleb galloped to the sideline pointing to the coaching staff before jumping into their arms.
Akpom slid home a second six minutes later.
"It's really an incredible story and we're all happy to experience it," said Lille coach Bruno Genesio.
"He hung on, he believed in himself, he believed in the people who took care of him.
"There were periods where we all wondered if he was going to play again or not. As time went by, we all had more and more confidence in him and in his ability to play again."
Genesio added: "Obviously, it was already a real victory for him, because he went through terrible times."
On a day when all five away teams won, Nice seized control in Le Havre through a 16th minute goal from Gaetan Laborde and an own-goal from Etienne Youte Kinkoue two minutes later.
Yassine Kechta replied for the hosts after 28 minutes.
Nice fullback Melvin Bard received his second yellow card in the final minute, but substitute Sofiane Diop sealed the win for the visitors with a goal deep into added time.
Nice regained the final guaranteed Champions League slot on goal difference from Monaco, who had hammered Nantes 7-1 Saturday.
Lyon took revenge for a home defeat earlier in the season with a 4-1 win at Montpellier.
Georges Mikautadze gave the visitors a third-minute lead.
Tanguy Coulibaly levelled before the break.
Lyon dominated the second half and struck through Ernest Nuamah, Corentin Tolisso and Alexandre Lacazette, with his 15th career goal against Montpellier.
Next up Lyon host league leaders Paris Saint-Germain.
"We'll be playing against the best team in the French league. We're going to prepare our strategy well, knowing that we've made good progress,” said Lyon coach Paulo Fonseca.
Strasbourg rose to seventh as they won 2-0 at Lens.
The hosts were reduced to 10 men when fullback Deiver Machado was sent off in the 72nd minute.
The visitors exploited their advantage with an 81st minute goal by Dilane Bakwa and a second, in the 96th minute, by Emmanuel Emegha.
Farid El Melali scored the only goal as Angers won 1-0 at Reims.
Saturday, Fabian Ruiz scored the only goal as PSG edged out Toulouse 1-0 to stay 10 points clear at the top of the table from Marseille, who thrashed Saint-Etienne 5-1.
RESULTS
Montpellier 1 (Coulibaly 38) Lyon 4 (Mikautadze 3, Nuamah 50, Tolisso 53, Lacazette 73)
Le Havre 1 (Kechta 28) Nice 3 (Laborde 16, Kinkoue 18-og, Diop 90+4)
Lens 0 Strasbourg 2 (Bakwa 81, Emegha 90+6)
Reims 0 Angers 1 (Melali 45+1)
Rennes 0 Lille 2 (Bentaleb 80, Akpom 86)
Saturday
Marseille 5 (Gouiri 27, 60, Greenwood 50-P, Murillo 58, Rabiot 77) St-Etienne 1 (Stassin 79)
Monaco 7 (Biereth 45, 54, 65-P, Minamino 45+1, Seghir 49, Ilenikhena 81, 90+5) Nantes 1 (Abline 5)
Toulouse 0 PSG 1 (Ruiz 52)
Friday
Brest 2 (Ndiaye 60, Ajorque 79) Auxerre 2 (Perrin 18, 74)
