The first round of group games get underway later.
Manchester United manager Ole Gunnar Solskjaer believes their summer signings have made them contenders to win trophies this season.
They begin their Champions League campaign later away to Swiss side Young Boys in Bern.
Cristiano Ronaldo, Raphael Varane and Jadon Sancho - who all joined in recent months - should feature.
Solskjaer says the squad's in a good place.
Kick off for their Group F clash is at 5.45.
Then from 8pm, holders Chelsea begin the defence of their title.
They have a home fixture against Zenit St Petersburg in Group H.
Elsewhere, Barcelona and Bayern Munich clash in Group E.
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