The north London side kick-off against the Spanish giants, who finished in third place behind Barcelona and Real Madrid in La Liga last year, at 21.00 at the Mestalla.
Assou-Ekotto believes that the challenge of facing a team that places an emphasis on possession will stand Spurs in good stead ahead of the new season.
"The Spanish teams love to keep the ball and press, so it won't be easy to keep the ball against them," Assou-Ekotto told the club's official website.
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"It will be hard but it will be a good game for us."
The full-back also looked towards Spurs' first game of the Premier League season against Newcastle on August 18 at the Sports Direct Arena and underlined the importance of a positive start to the campaign.
"It's a difficult place to play but we all want to win the first game, it’s important to have a good start," he added.