Van Aert wins Vuelta stage seven as O'Connor stays in red jersey
Czech rider Mathias Vacek (Lidl-Trek) came in second ahead of Spain's Pau Miquel Delgado (Kern Pharma) in third, with the red jersey of O'Connor finishing safely in the leading bunch.
The 180.5km ride from Archidona to Cordoba included one categorised climb, Alto del 14%, late in the stage, but with 26 kilometres to the finish, and a flat run after the descent, a bunch sprint was the expected outcome.
O'Connor (Decathlon-AG2R La Mondiale), who took the red jersey after winning stage six, has a four-minute 45 seconds lead over three-times former champion Primoz Roglic (Red Bull-Bora-Hansgrohe).
The pace set by Red Bull and Roglic on the climb brought a split in the race, with a leading bunch of 33 riders left to battle for the stage win.
"I expected it to be a way bigger group to go to the finish. I knew the climb on the circuit was hard but I didn't expect that the race would explode like it did," Van Aert said.
Australia's Kaden Groves, winner of stage two, crashed as he attempted to make his way back to the leaders, which took one of Van Aert's main rivals out of the final sprint.
Marc Soler (UAE Team Emirates) attempted to get away on the descent, and it was Van Aert who went in pursuit but he then let his teammate and defending champion Sepp Kuss take over the work.
"We always had this stage in mind for Wout but we knew it would be hard, especially with the pace on the last climb," Kuss said.
"The pace was hard but when I saw Wout there I knew he was on a good day. It was a 'sufferfest' to pull Soler back but it feels like a victory for me too."
Soler was reeled in, and then his teammate Pavel Sivakov went early to try and steal a march, but once he was caught and Van Aert took to the front towards the line, the winner was never in doubt.
Van Aert strengthened his hold on the points jersey, and the Belgian who won stage three and finished second on two other stages, had the unselfish work of his American teammate to thank for this win.
"Sepp did such an amazing job, I don't think people know what it's like when you're below 60kg and you do those kinds of pulls on the flat," Van Aert said.
Pre-race favourite Roglic only managed to take six seconds off O'Connor's impressive lead, taking the bonus seconds when he was first at the top of the climb.
"I can't really do much against Primoz's sprint for the bonuses, but you have to take a lot of bonuses to make up that amount of time," O'Connor said.