© Getty Images
After a cagey opening 10 minutes, the first real chance of the match fell to the visitors as Fernandinho played the ball in for Raheem Sterling, leaving the England international to unleash a shot from the edge of the area, but the finish was deflected wide.
The hosts started to dominate possession, but United were unable to make the most of a free kick into the box from Juan Mata, while the Spaniard was involved again a few moments later, failing to connect with Ander Herrera.
Louis van Gaal's side continued to grow in confidence as the half-hour mark approached, despite Wayne Rooney picking up a cut to his head, creating space for Anthony Martial to weave past two defenders before playing the ball in for Mata, but his pass to Rooney went astray.
City forced a free kick in a promising position down the other end, but Bastian Schweinsteiger was on hand to clear Kevin de Bruyne's delivery, while a cross in from Sterling a couple of minutes later failed to find any of his teammates.
The visitors continued to look the more likely in the final five minutes of the half, with Yaya Toure coming close with a header after the Ivorian forced a corner, but the midfielder was unable to test David de Gea with his effort.
There was time for the home side to get the ball back towards the City goal though, but Valencia conceded a free kick while trying to set something up, while a Rooney delivery in from out wide was cleared by the City defenders.