The former Barcelona goalkeeper was called into action after United number one David De Gea was forced off with a hamstring problem.
Valdes has found his first-team opportunities limited since he moved to Old Trafford on a free transfer in the January window.
However, the Spain international was delighted to finally make his debut despite conceding a goal in a disappointing 1-1 draw with Arsenal yesterday.
Valdes told United’s website: “It felt very good.
“David asked to come off very quickly and the next thing I knew I was on the pitch. It was a great feeling to be on the pitch at Old Trafford, the fans welcomed me very well and for that reason I am happy.
“I wasn’t happy with the result because it wasn’t a good one for us. It was a lucky goal for them, but I’m happy I made my debut. It was all very quick: David came off and I didn’t know what was happening, but then someone said ‘Victor, get in there'”.
“It’s been a good few months; my team-mates have treated me well here. The coach has also treated me well. The truth is that it has all been good. We have an incredible group of fans – to come on and be welcomed like that is incredible for a footballer.”
The former Barcelona goalkeeper joined United in January after the 33-year-old had spent a number of months training with the 13-time Premier League champions.
De Gea, who was named in the PFA team of the year, has been linked with a move to 10-time Champions League winners Real Madrid in the summer transfer window.
Valdes is being tipped to become the club’s new first-choice goalkeeper if his team-mate does seal a move to Madrid.
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