The riders started early in the morning for the 25th edition of the midweek Ardennes classic. After an attacking opening phase, a five-rider breakaway got away from the pack. Ten other riders joined halfway through the race, including Koster.

The group got a three-minute lead, but the peloton increased the pace on the climbs. When the leaders were almost caught, Koster accelerated and got a small gap on the group.

At the top of the Cote de Cherave, Koster was caught by the favourites. Together they went to the final passage of the Mur de Huy and on this grueling climb, she had to let the punchers go.

"I felt great today”, Koster said. “I was in a very nice leading group. We kept it up almost to the end. We got a two-minute lead and I thought: maybe we make it to Huy. Unfortunately, we only had ten seconds left on the penultimate climb, after which I decided to attack."

"I had a nice gap, but I was caught by the best of the bunch, just before the top. When we started on the wall with this group, I was empty."