Manchester United got off to a bad start in their Champions League campaign with a defeat in their opening group stage game away to PSV Eindhoven. They lost 2-1 with an own goal from Daley Blind and a fine header from Luciano Narsingh which cancelling out Memphis Depay's opener, but what did we learn?

Van Gaal's substitutions are confusing

Not for the first time this season when trying to search for a goal Louis van Gaal's substitutions have raised some serious questions as they just were not the right ones to make. It was even more evident in the PSV game when bringing on Marouane Fellaini for Ander Herrera, which was a very strange substitution to make as it signaled that United were going to go long ball from 70 minutes on which should not be happening.

Options from the bench are very limited

The bench that United had for the PSV game was very limited when it came to attacking options, but that was the manager's fault as he should have at least had James Wilson on there as he would have been perfect for the game. Another option could have been Andreas Pereira to play as he is a creative midfielder and would have been a good option to open up the PSV defence.

In the summer it was the perfect opportunity for Van Gaal to make sure that when he sold players such as Robin Van Persie and Javier Hernandez, he brought in suitable replacements, but he didn't do that and couple that with Wayne Rooney's hamstring injury, United's attacking options are very limited which is a massive problem.

Luke Shaw is going to be a big miss

Luke Shaw had such a superb start to the season but after his awful injury against PSV he'll be out for months and will be a massive miss for United. When Shaw went off during the game United lost a real attacking threat down the left side as Marcos Rojo doesn't have the pace and penetration that Shaw has, so therefore going forward United will be lacking in that area.

Martial looks a very good player

The big positive that came out the game against PSV was Anthony Martial and his link up play which was very good. There were already signs of a good understanding between the players and Martial and some of the touches that Martial produced during the game gave United so many chances to get into a good position.

United fans can't expect Martial to be able to score every game, but they can see the movement of the youngster and the way he stretches the defence which means United have a very good player on there hands, but it could take a while before he produces every single game.

Mata in the number ten role didn't work

Every United fan has been calling for Juan Mata to be utilized in the number 10 role in Van Gaal's system, and he was given the chance in the game against PSV but had a very poor game and it will probably be the last time he plays there. Mata missed a big chance when Bastian Schweinsteiger played him through and he missed it, and another thing was his passing as it was very off which really was very disappointing.