Manchester United manager Louis van Gaal has praised the "unbelievable" Marcus Rashford after his debut brace helped his side progress into the next round of the Europa League.

After Anthony Martial suffered a hamstring injury during his final warm-up, Rashford, 18, was thrown into the starting XI and repaid his manager's faith with two memorable goals in front of the Stretford End as United eased to a 5-1 win over Midtjylland.

Speaking to BT Sport post-match, van Gaal revealed he had to instruct the teenage striker to alter his game slightly at half-time, a move he was delighted to see pay off.

"It is unbelievable, in the first half he ran too much to the side lines, and I said at half time you have to be in the width of the goal and then you should score. And you see, he [then] scores two goals, it is fantastic for him."

Rashford gave Midtjylland a first-half warning when he skipped past his marker just inside the box, only to see his shot saved by Mikkel Andersen. An own goal from Nikolay Bodurov – forced by the excellent Memphis Depay – ensured United went into half time level after Pione Sisto's opener, but it was Rashford's brace that changed the game.

The young striker was alive to Juan Mata's ball back across goal after 63 minutes, darting in front of his marker to slot home. He repeated the trick just 12 minutes later, finding space for himself in the six yard area to convert Guillermo's Varela's cross.

Another Midtjylland goal at this point would have seen the Danes progress on away goals, but Ander Herrera eased those concerns with a powerful penalty with three minutes remaining, before Depay crowned an outstanding solo performance with a well-taken strike on 90 minutes.