In a dress rehearsal of the Coupe de la Ligue final this coming weekend, PSG struggled again without leading scorer Zlatan Ibrahimovic. By contrast, Lyon continued their late push for a place in Europe, buoyed by the news that Saint-Etienne could only draw away to Stade de Reims earlier in the day.
Les Gones' chances of finishing inside Ligue 1's top four looked dead and buried after they were beaten by Saint-Etienne at the end of March. The 2-1 reverse in the Rhone derby at Stade de Gerland last month left Remi Garde's side trailing Saint-Etienne by six points with only seven games remaining.
However, Saint-Etienne have drawn twice since that match, while Lyon have recorded back-to-back league victories and now find themselves right back in contention for the one Europa League place available.
Jordan Ferri's opportunistic strike after half an hour was enough to see off a subdued PSG side, who failed to score in consecutive games for the first time this season. Laurent Blanc's men were left to rue the continued absence of Ibrahimovic as Edinson Cavani again failed to find the back of the net.
Cavani was criticised on both sides of the Channel for his performance against Chelsea in midweek, and he cut a frustrated figure against Lyon. Playing in his preferred position at the head of the attack, the Uruguayan was brilliantly denied by Lyon goalkeeper Anthony Lopes inside the opening two minutes, seeing his sharp flick saved at the near post.
Lyon's goal came against the run of play. Ezequiel Lavezzi misplaced a pass midway inside his own half and Ferri drove on to the ball, curling a right-foot shot past the unsighted Sirigu into the back of the net from range.
Lyon rode their luck as PSG pressed for an equaliser, but unlike Les Parisiens in midweek, they held on to their clean sheet. Javier Pastore had an excellent late chance to equalise, but the superb Lopes dashed quickly off his line to deny him.
With the gap just two points, Lyon will be confident that they can overhaul their Rhone rivals and finish in the top four. They now have the vital element of momentum which often plays such an important role as the season comes to an end.
What will also be particularly pleasing for Lyon is the important role their young players have had in their season.
The aptly named Les Gones have a renowned academy, and 25 of their 49 Ligue 1 goals have been scored by youngsters who have risen through the ranks to join the first team. Alexandre Lacazette has been the most impressive, but Ferri's strike against PSG takes his total to three for the season.
PSG's trip to Stade de Gerland was a dry run for the Coupe de la Ligue final this coming weekend. Blanc's side will undoubtedly be the favourites, but Lyon's victory will have given them confidence ahead of the game at the Stade de France.
Winning the Coupe de la Ligue guarantees Lyon a place in Europe, but Garde's side have their eyes firmly fixed on overhauling their Rhone rivals Saint-Etienne and stealing fourth place.