Takumi Minamino scored the opener and was involved in each of Monaco's three other goals in a 4-1 victory over Ligue 1 opponents Clermont on Saturday.
The result guarantees Monaco, currently second in French football's top flight, can finish no worse than the play-off spot for next season's Champions League.
Minamino took his season tally to nine league goals when he curled a shot from the penalty arc into the top right corner in the 16th minute at Monaco's Stade Louis II.
"I controlled it properly and it carried nicely to where I was aiming," he said.
The Japan attacker helped set up Breel Embolo to retake the lead at 2-1 before being denied a second goal by Clermont keeper Mory Diaw's diving save late in the half.
Minamino contributed to back-to-back goals from Wissam Ben Yedder that sealed the result for the home side. He found the French striker with a deflected ball in the 57th minute and assisted him half an hour later by playing it square at the edge of the area.
The Samurai Blue veteran said he hoped for further goals before the end of the season.
"I had chances that may have led to a hat trick. I want to score more in those situations," he said.
In the Scottish Premiership, Kyogo Furuhashi netted twice, once with an assist from Japanese compatriot Reo Hatate, to help keep Celtic's title defense on track with a 3-0 win at home to Hearts.
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