Spain face Portugal, a country whose domestic league implemented VAR at the start of last season, in their opening Group B game next Friday.
Spain's La Liga will introduce VAR next season, meaning few players in the Spain squad have experienced a match refereed with the help of video and Lopetegui highlighted the need to be prepared mentally as well as physically for the stoppages.
“Portugal are used to the new system and Spain aren’t,” he told a news conference ahead of Saturday’s friendly against Tunisia in the Russian city of Krasnodar.
“When there’s a stoppage that we’re not used to, we will need to ensure we are fully focused in order to take advantage and be ready for the restart. There’s been examples of it working well and not so well for teams.”
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The president of the Spanish Referee’s Association, Carlos Velasco Carballo, spoke to the squad on Friday ahead of the tournament and explained how the VAR system works.
"The talk that we were given has helped us all a lot and cleared up a lot of the doubts we might have had,” Lopetegui said.
"There’s no point kicking up a fuss – VAR is being used and it is here to stay. We need to accept it and adapt ourselves to it."
The coach confirmed that Real Madrid defender Dani Carvajal is almost certain to be included in his final squad.
The fullback, who came off injured in his club’s Champions League final victory over Liverpool at the end of last month, was named in Spain’s initial 23-man squad last week.
Yet squad changes are permitted until 24 hours before a country’s first game, with Carvajal's club mate Jesus Vallejo having travelled to Russia on standby.
Lopetegui, however, eased fears over Carvajal’s participation.
“We need to support him. He’s going step by step and we’re happy with his recovery. I have no doubts that he’ll be alright, if not for the first game then for the second, but he’ll be ready, of that I’m sure.”
(Editing by Toby Davis)
