Erik ten Hag had brought Cristiano Ronaldo and Harry Maguire back on the field, they who had missed most of the matches won by the Red Devils since the start of the season.
Patatras, the Mancunians were surprised, on a penalty from Mendez on the hour mark.
Among the other major championships represented in C3, La Liga shone because Betis Sevilla also won, in Finland, on the lawn of Helsinki (2-0).
But the Italians did a little less well: Lazio won a suspense match against Feyernoord Rotterdam (4-2) but AS Roma lost 2-1 at Ludogorets.
The greatest show of force came from the French clubs, since Monaco won in Belgrade (1-0) against Red Star, on a penalty from Breel Embolo, while Rennes won in Cyprus against Larnaca (2- 1), at the last second, and Nantes at home against Olympiakos, on the same score, and also at the end of the suspense.
Finally, in the Europa League Conference, Villarreal and West Ham honored their status as favorites, but not without difficulty.
The English trailed 1-0 but won 3-1 against Romanian side Steua Bucharest.
The Spaniards of the "yellow submarine", semi-finalists of the C1 last year, snatched victory from the Poles of Lech Poznan (4-3).
© 2022 AFP