(Photo credit: Mike Frey-Imagn Images)

Competing in the event for the first time since 2017, Croatia's Marin Cilic kicked off grass-court season with a 6-7 (5), 6-4, 7-5 upset of seventh-seeded Canadian Denis Shapovalov in opening-round action of the Libema Open Monday at 's-Hertogenbosch in the Netherlands.

Cilic trailed 4-2 in the second set before rattling off four straight games to level the match. He again fell down a break in the third set, but broke Shapovalov in each of his final three service games, converting 7 of 10 break-point chances.

Next up for Cilic will be Portugal's Nuno Borges, who swept France's Terence Atmane 6-4, 6-4. Borges had just two aces to Atmane's 13 but had nearly half as many unforced errors (12 to 23) and never faced a break point.

No. 5 seed Ugo Humbert of France faced little resistance in a 62-minute 6-4, 6-3 defeat of Swedish qualifier Elias Ymer in the final match of the day. He'll next face countrymate Benjamin Bonzi, who defeated 18-year-old Dutchman Mees Rottgering 6-4, 6-4.

BOSS Open

Italy's Mattia Bellucci knocked off No. 7 seed Spaniard Alejandro Davidovich Fokina with a 6-2, 6-7 (5), 6-1 win in a first-round match at Stuttgart, Germany.

After coming up short of a sweep in the second-set tiebreaker, Bellucci dominated the third set, jumping out to a 5-0 lead. Despite hitting just 48% of his first serves in the deciding set, he won 74% of his service points and converted five break points in the match to Davidovich Fokina's one.

Another Spanish competitor, Martin Landaluce, recorded his first tour-level win on grass Monday, beating France's Pierre-Hugues Herbert 5-7, 6-3, 6-4. He'll have his hands full in the second round against No. 2 seed and defending champion Taylor Fritz, who got a first-round bye as a top-four seed.

Belgian qualifier Gauthier Onclin beat Hungary's Fabian Marozsan 7-6 (6), 6-3, and awaits the winner of the match between France's Giovanni Mpetshi Perricard and Russian lucky loser Roman Safiullin, which was suspended due to rain with Safiullin ahead 4-1 in the third set.

--Field Level Media