About a decade ago, Unai Emery was talking about his dream of one day winning the Champions League.

He was coaching Valencia, which was in the group stage a year after reaching the last 16 under his command.

Emery couldn’t lead the Spanish club to the knockout rounds again at the time, and the last 16 was the closest he's ever got to a Champions League trophy.

He couldn’t do any better with Valencia or his other clubs since then: Spartak Moscow, Sevilla, Paris Saint-Germain and Arsenal.

But at Villarreal, he has another chance. The small Spanish club hosts Juventus in the first leg of the round of 16 on Tuesday.

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“You don’t get to play in the Champions League every year, so you have to enjoy it when you do,” Emery said on Monday. “You have to give it all you have. We are not the favorites but we have shown that we can overcome teams of the level of Juventus. We have shown that we deserve to be where we are right now.”

Villarreal is making its first appearance in the round of 16 in 13 years and enters as the underdog against a Juventus squad that reached the final five years ago but hasn't gotten past the last 16 in the last two seasons.

“The tie isn’t decided yet. Villarreal is going through a good moment, and so are we,” Juventus coach Massimiliano Allegri said. “Villarreal is a technical team with a great coach. It will be a very tactical match, where we will have to pay attention to details and have patience.”

It will be Emery’s fourth attempt to reach the quarterfinals after failing with Valencia in 2011 and twice with PSG in 2017 and 2018.

In his other three Champions League appearances, Emery failed to advance his team past the group stage while with Valencia in 2011-12, Spartak Moscow in 2012-13 and Sevilla in 2015-16. He didn’t reach the group stage with Villarreal last season, nor with Arsenal the previous two years.

Emery's European success came in the second-tier Europa League, which he won three times with Sevilla from 2014-16 and once with Villarreal last season. He also was runner-up with Arsenal in 2019.

“I always like to try to learn from others but I never lose my essence,” Emery said. “There are a lot of secrets to be successful, and mine is to always work hard.”

The Spaniard wasn't able to thrive at PSG and also couldn't meet expectations at Arsenal, where he was often mocked for his poor English while enduring the difficult task of succeeding coach Arsene Wenger.

Emery led Villarreal to the knockout stage of the Champions League this season from a group that included Manchester United, Atalanta and Young Boys, while Allegri’s Juventus advanced from a group with Malmo, Zenit St. Petersburg and defending European champion Chelsea.

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Villarreal, a Champions League semifinalist in 2006, is unbeaten in four matches in all competitions and Emery will have forward Arnaut Danjuma in top form after he was sidelined for nearly two months because of an injury. The Dutchman scored a hat trick on Saturday in Villarreal’s 4-1 win at Granada in the Spanish league.

Juventus was eliminated by Porto and Lyon in the round of 16 the last two seasons on the away-goals rule that has now been scrapped. Allegri's team is coming off two straight draws in the Italian league and has only one win in its last four games in the competition.

The Italian coach will not be able to count on forward Paulo Dybala and defender Giorgio Chiellini because of injuries, but he will have available new signing Dusan Vlahovic, the 22-year-old Serbia striker who arrived from Fiorentina amid high expectations.