Sir Alex Ferguson would not have been impressed as Michael Carrick gave away possession and Alejandro Dominguez made an incisive pass to Pablo Hernandez, who fired the ball underneath the legs of Ben Amos.
The Spaniards were now on course to top the group at the expense of United who had targeted the summit as a means of avoiding the fancied clubâ€™s in the knock-out stage.
The hostâ€™s were creating chances but not taking them and their luck seemed out when Wayne Rooney hit the crossbar.
But United breathed a sigh of relief in the 62nd minute as a Ji-Sung Park shot could only be parried by Vincente Guaita and Anderson forced home the rebound.
The Reds must still wait for their 150th win in UEFA competition but overall it was mission accomplished and hopefully a kind draw in the knock-out phase.
Referee: Pedro Proenca (Portugal)
Venue: Old Trafford Attendance: 74,513
Man Utd scorers: Anderson 62 Valencia scorers: Pablo 32
MAN UTD 40 Amos 05 Ferdinand (Smalling 50) 15 Vidic 20 Fabio Da Silva 21 Rafael Da Silva 08 Anderson (yellow card) (Fletcher 90) 13 Park Ji-Sung 16 Carrick 17 Nani (Giggs 81) 09 Berbatov 10 Rooney
Substitutes 29 Kuszczak, 12 Smalling, 11 Giggs, 24 Fletcher, 14 Hernandez, 26 Obertan, 27 Macheda
VALENCIA 13 Guaita 15 Angel Dealbert 20 Costa 22 Mathieu 23 Miguel (yellow card) 06 Albelda (yellow card) 19 Pablo (Feghouli 81) 21 Banega 28 Ramos Jordi Alba (Mata 67) 08 Dominguez (Isco 54) 11 Aduriz
Substitutes 01 Cesar, 03 Maduro, 12 Feghouli, 24 Facundo Costa, 09 Soldado, 10 Mata, 26 Isco