Substitute Julien Gorius scored the only goal as Genk got their Europa League Group G campaign off to a good start away to Dynamo Kiev.
Gorius netted two thirds into the tie when he scored from the edge of the area as Dynamo failed to get on the scoresheet.
Dynamo started brighter and Lukman Haruna saw his shot from Jeremain Lens' corner blocked by Genk's Kara Mbodji.
Genk goalkeeper Laszlo Koteles then saved his side when he tipped a long-range shot from Haruna around the post before Andriy Yarmolenko was off target.
Brown Ideye had another shot for Dynamo but his close-range effort was blocked by Mbodji.
Genk's first chance fell to Bennard Kumordzi whose long-range shot was tipped around the post by Dynamo keeper Maksym Koval.
Koval was then on hand to keep out efforsts from Jelle Vossen and Ilombe M'Boyo as Genk came more into the game.
Yarmolenko's shot from 20 yards was kept out by Koteles as Dynmao tried to reassert their early control.
Ideye tried his luck from distance before Kumordzi forced Koval into a fine save, the keeper tipping his shot out for a corner.
Koval denied Vossen and M'Boye and Genk keeper Koteles saved twice from Yarmolenko in quick succession.
As half-time approached both sides went close, Lens forcing Koteles into a save before Genk's Thomas Buffel missed the target from close range.
Genk broke the deadlock just after the hour when Gorius fired in from the edge of the area.
Lens shot over the bar and then the home side created three more chances but Yarmalenko's shot was saved by Koteles, Lens headed wide and Koteles then saved from Roman Bezus.
Dieumerci Mbokani had two late chances but shot wide before his header also failed to beat Koteles.
The Genk keeper was booked for time-wasting two minutes into stoppage time and then earned his side the win with a fantastic save from Yarmolenko's shot.