Lens moved into the final of the Coupe de France for the first time since 1998 following a 4-1 annihilation of Toulouse on Tuesday night at the Stade Bollaert-Delelis.
Lens striker Florian Thauvin opened the scoring from the penalty spot after nine minutes. And the 33-year-old France international laid on the pass for Allan Saint-Maxim to double the host's advantage 10 minutes later.
Santiago Hidalgo halved the deficit mid way through the first-half but Matthieu Udol restored the two-goal lead just before half-time. Adrien Thomasson added the gloss in the 75th minute.
On 22 May at the Stade de France in Saint-Denis, Lens will play the winners of Wednesday night's second semi-final between Nice and Strasbourg.
Possible league and cup double
Lens, with 62 points after 29 games, are also in a race for the 2026 Ligue 1 title.
On Wednesday night, Ligue 1 pacesetters Paris Saint-Germain have a chance to extend their lead to four points over second-placed Lens.
PSG entertain relegation-threatened Nantes at the Parc des Princes in Paris.
"The struggling sides are in last chance saloon when it comes to staying in Ligue 1," said PSG boss Luis Enrique on the eve of the clash.
"Playing against them is really hard. If any fan is expecting to come to the Parc des Princes just to drink Coca-Cola and have something to eat, forget it! If you're expecting an easy game, forget it!"
Lens boss urges squad to relish chase for first Coupe de France
Following Wednesday night's match, PSG, who are chasing a fifth consecutive top flight crown and a record-extending 14th overall, will have five games left including what could be a title decider at Lens on 13 May.
The match should have been played on 11 April but the Ligue de Football Professionnel, which runs Ligue 1, dismissed Lens' objections and allowed PSG to postpone the fixture as part of their preparations for the second leg of their Champions League quarter-final against Liverpool.
PSG conclude their Ligue 1 campaign on 16 May at Paris FC while Lens play the same day at Lyon who are fighting to finish in the four places in Ligue 1 which lead to a berth in the league stages of the 2026/2027 Champions League.
