Last Saturday, Van Gaal's reign at Old Trafford began with a 2-1 loss to the Welsh outfit, prompting fans to question the quality of the squad.
"Two weeks ago I was the king of Manchester. Now I am the devil," Van Gaal said in this afternoon's press conference. "I was not hired to be fired, but to build up a team, and that is a process that needs time."
When asked about the concerns that supporters have regarding the lack of spending so far this summer, Van Gaal replied: "The fans can think like that but it's not easy trying to buy and sell in the football market."
The former Netherlands boss took over at the North-West outfit after David Moyes was sacked in April following a disastrous campaign, which left the Red Devils seventh in the Premier League.