Movistar’s sporting director accused cycling’s governing body of favouring Vuelta a España leader Primoz Roglic on Friday after the Slovenian was allowed to use a car’s slipstream to catch up with the peloton after a crash.

The issue arose just over 100km into the rain-affected 19th stage from Avila to Toledo when a group including Roglic and fourth-placed Miguel Ángel López crashed heavily on a descent. Roglic’s teammate Tony Martin was forced to abandon the race following the incident.

“If this is cycling and the UCI decides who is going to win, well perfect,” said Movistar’s José Luis Arrieta said. “This kind of thing has happened to us and they didn’t take this decision.”

The UCI did not immediately respond to a request for comment.

Cycling etiquette dictates that if a race leader suffers a crash or mechanical problem then the rest of the race waits for him to recover and rejoin the peloton. In this instance, immediately after Roglic hit the deck Movistar attacked, drawing fierce criticism from commentators and other members of the peloton. Team Ineos’s Owain Doull told Eurosport: “It depends if they were riding out ahead beforehand – if they weren’t then that was shocking. It’s not like they did it for a few kilometres and then sat up, it was pretty divided for a while. If I were Roglic and Jumbo I wouldn’t be happy. I’m not happy and it had nothing to do with me.”

Roglic and López were then led back to the main group by drafting in the slipstreams of team cars, which is not permitted under normal circumstances.

Arrieta claimed his team had always planned to attack following the short downhill stretch and that their positioning in the peloton was justification for their manoeuvre. “We were always going to attack where the crosswinds would come into play and we were at the head of the pack for a reason,” he said. “We spent hours and hours doing recons. Obviously I don’t like crashes but we’ve lost races because of crashes. I told them to stop only when the UCI said that they would allow riders to use the cars to catch up.”

Riders in action during the 19th stage. Photograph: Javier Lizón/EPA

Movistar riders Alejandro Valverde and Nairo Quintana are second and third respectively, and it was Valverde who relayed the order for the rest of his teammates to slow down as Roglic and López rejoined the main peloton.

In just his second grand tour, France’s Rémi Cavagna claimed a first-ever stage win after riding away from the breakaway with 24km to go. He finished five seconds ahead of the chasing peloton, who caught the rest of the break with just over one kilometre of the cobbled uphill finish remaining.

Roglic leads Valverde by 2min 47sec with Saturday’s 190km mountain stage – containing five climbs – from Arenas de San Pedro to Plataforma de Gredos realistically the world champion’s final chance to claw back time on the Slovenian.