The 22-year-old scored the Netherlands' third gold medal of the week after a perfect run-in to the line for her and her team. Her Dutch teammate and lead-out woman Scarlett Souren finished off a one-two in second place.
Eleonora Gasparrini finished third to take bronze – Italy's fourth medal of the Championships.
Van Rooijen's win came after her Dutch squad had controlled the final kilometres of the 101km race, run over flat roads between Heusden-Zolder and Hasselt. The team, which also included Ilse Pluimers and Nienke Vinke, shut down attempted late attacks by several Italian riders as well as Julia Kopecky (Czechia) and Wilma Aintila (Finland) to ensure a bunch sprint finish.
Earlier, Belgium had attempted several moves to send riders clear once the early break of Mikka Holm (Denmark) and Nela Slanikova (Czechia) had been reeled in, though no big names managed to slip clear and disrupt the sprint. As the race hit the final of the local laps around Hasselt some 14km out, a crash took several riders out of contention.
Finnish sprint hope and newly crowned U23 time trial champion Anniina Ahtosalo was among them, with the 21-year-old eventually rolling home in 74th place at 1:42 down.
The Dutch team came through unaffected, however, keeping the lead group together for the finishing sprint, where Souren delivered a textbook lead out for her trade teammate Van Rooijen, staying close to take silver as Van Rooijen sped ahead to the blue-striped jersey of European U23 champion.
Dani Ostanek is Senior News Writer at Cyclingnews, having joined in 2017 as a freelance contributor and later being hired full-time. Before joining the team, she had written for numerous major publications in the cycling world, including CyclingWeekly and Rouleur. She writes and edits at Cyclingnews as well as running newsletter, social media, and how to watch campaigns.
Dani has reported from the world's top races, including the Tour de France, Road World Championships, and the spring Classics. She has interviewed many of the sport's biggest stars, including Mathieu van der Poel, Demi Vollering, and Remco Evenepoel, and her favourite races are the Giro d'Italia, Strade Bianche and Paris-Roubaix.
One of just three riders from nation lining up to take on the brutal cobbled test, the second-youngest rider in race is first Australian across line in 82nd place
