Rojo helped Man United keep a clean sheet as they were held to a 0-0 draw at Old Trafford and he was hugely important in keeping City at bay.
The Argentine was responsible for looking after Kevin De Bruyne in the first half and did so with relative ease, as the Belgian playmaker struggled to impose himself on the game.
City found it extremely difficult to find any joy down their right hand side as Rojo consistently thwarted their attacks and provided ample support for Anthony Martial ahead of him.
“He had a very good match, with good passes and good crosses. I’m very satisfied with him,” van Gaal said.
Rojo had a disappointing outing in midweek during United’s trip to CSKA Moscow as the Russian side identified him as a weak link. CSKA looked to isolate the 25-year-old and succeeded as they found all sorts of joy down their right flank.
However, City had no such luck. Unlike the game in Moscow, Rojo found himself getting forward much more and was involved ahead of Martial on a number of occasions. The left-back seemed intent on getting the ball out of his feet and whipping a cross into the box but was unfortunate that none of his deliveries found someone in a red shirt.
Regardless of the result, United fans will be buoyed by Rojo’s display. With Luke Shaw set to be out for the majority of the season, the Reds are desperate for a full-back who can make that spot their own. Rojo showed signs against City that it could be his position and he will want to build on his showing and make a claim for the position.