The Argentine believes it will only be a short time before United are successful again.
The Dutchman was brought in to replace David Moyes last season following the Scot's disastrous year in charge of the Old Trafford outfit and guided them back into the Champions League after they missed out the year before.
A fourth-placed finish is not good enough for the Manchester United faithful, though, with silverware an expected achievement. That was something the Dutchman failed to bring back last term but Argentine defender Rojo isn’t concerned, insisting he will bring trophies back in the future.
"Louis van Gaal will be successful at Manchester United. He will win trophies. For me, that's not even a question," the London Evening Standard reports him as saying.
"From the first training session he took, we could tell he was a winner. He's very demanding. Being demanding and asking a lot is a sign of a real winner and it will only be a short time before Manchester United are winning trophies again."
Big signings needed to compete at the top
If Van Gaal is to bring trophies back to Old Trafford, he will likely have to spend big to do so.
All of United’s rivals are likely to continue improving this summer, with Chelsea already having a strong squad as it is and Manchester City looking to overhaul an ageing side.
Arsenal will also be keen to build on last campaign and have already secured Petr Cech to do so, while even the likes of Liverpool have been busy early on this summer.
All of that will increase the pressure at the top of the league and make it even more of a challenge to secure a top-four finish, never mind Premier League success. For now, then, perhaps Manchester United should focus on reaching the Champions League rather than eyeing the title. How about the FA Cup?