The goalless Barclays Premier League clash at Old Trafford disappointed as a spectacle in terms of attacking flair, but there were plenty of decent performances on show.
Most of those came from the defensive-minded players, and Rojo was very much among them, doing a fine job at left-back of keeping the likes of City forward Kevin De Bruyne at bay.
It had looked as if Rojo might leave United over the summer, with Van Gaal reportedly angry at the Argentina international that passport issues had prevented him from joining up with the club's pre-season tour
The manager also recently claimed Rojo had failed to tell him about a hamstring injury he suffered.
But regarding what was only Rojo's third league appearance of the campaign on Sunday, Van Gaal told MUTV: "Rojo played a very good match, not only against De Bruyne but also against (City substitute) Jesus Navas
"He had very good passes and very good crosses so I am very satisfied with him.
"It is only his third game this season; he has hardly played for 90 minutes
I am very happy that at last he has the condition to play a full match."
On the other side, there were also compliments being paid to another Argentina defender in City's summer signing Nicolas Otamendi, who put in an impressive display himself at centre-back alongside returning Blues captain Vincent Kompany.
City goalkeeper Joe Hart, quoted on the club's official website, said: "Nico has come in and adapted very quickly which is something we expected, but respect to him because it's not an easy league to come into.
"He had a tussle with (Wayne) Rooney all afternoon and (Anthony) Martial out on the wing.
"It was a big occasion for him but he slipped in alongside Vincent and played really well - we're blessed to have so many good centre-halves at this club and Nico is definitely one of them."
The stalemate saw City return to the top of the table on goal difference ahead of second-placed Arsenal, while United are two points worse off in fourth.
Hart added: "It's a performance that's good to know we have in the locker, though I'd have preferred it if we hadn't have had to use it.
"We came looking to take three points but respect to Man United who were set up well and they caused us a few problems further up the field, but we defended well and limited them to two half-chances.
"We don't want praise - we just want points
We wanted all three but we took one and it was what was required to put us back on top of the table
Now we just need to kick on again."
Source : PA
Source: PA