Villarreal boss Unai Emery has admitted Group F is wide open after the opening round of matches.
Manchester United lost 2-1 to Young Boys, while Villarreal and Atalanta drew 2-2.
Emery’s Villarreal visit Old Trafford next in a repeat of May’s Europa League final.
Speaking to Villarreal’s website, Emery said: “This group gets complicated with Young Boys beating Manchester United.
“I wouldn’t rule out a surprise, because I’ve already experienced them in the Champions League and in the Europa League.
“Teams in Europe have a touch more motivation. Young Boys are group leaders, and Manchester United, who are the favourites, are last.
“Atalanta and Villarreal are there, fighting for our space. Every game played makes it that little bit harder.”
Tough game upcoming
United have never beaten Villarreal in a competitive game, drawing 0-0 four times before the 1-1 Europa League final which went to penalties.
The La Liga side have kept the core of their team intact from last season, holding onto star defender Pau Torres and top goalscorer Gerard Romero.
Defender Juan Foyth sent a message on social media after their draw with Atalanta, which read: “It is a difficult group, we will face all the games as if they were finals.”
United won’t have it easy against them, even with revenge for Gdansk on the mind.
Villarreal are resilient, well drilled, with a goalscoring threat, and the tense situation in the group with United needing a win, will only make it tougher.
Then there are two games upcoming against a dangerous Atalanta side which gained more Serie A points than Ronaldo’s Juventus last season and reached the Champions League quarter-finals in 2019/20.
The Young Boys games should have been six points in the bank for United. Now with one game lost already, United are up against it.
As Emery points out, the group is ‘complicated’, and all four sides will fancy their chances of progression.
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