Former Netherlands boss Van Gaal signed a three-year contract when he took over three months after the sacking of David Moyes, who endured a miserable 10 months in charge after replacing the retired Sir Alex Ferguson.
It is unclear whether the 64-year-old Dutchman will see out his final season at Old Trafford, although he said he is “confident” of being in charge.
A number of United supporters have called for the former Ajax, Barcelona and Bayern Munich manager to leave, while some boos could be heard as he addressed the home crowd on a microphone after the final game against Bournemouth.
Van Gaal could lead United to their first major trophy since 2013 – the Premier League title under Ferguson – when they face Crystal Palace in Saturday’s FA Cup final at Wembley.
But he admitted finishing fifth is a step back after guiding the Red Devils to Champions League qualification in his debut season.
“Our aim in the first year – and also the second and the third – is the Champions League,” he said after the 3-1 win over Bournemouth.
“It is the highest level and a club like Manchester United has to play at that level.”
However, he also warned supporters against dreaming too big.
“The expectation is very high,” he said. “The fans are expecting a lot but I think these expectations are much too high.”
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