The Bulgarian, who is set to start alone up front for the Red Devils, has continually come in for criticism for his languid style, and was the subject of scepticism again at the weekend following a lacklustre performance against Chelsea.
Yet the Bayern boss, who previously attempted to sign Berbatov, still holds the striker in high regard.
"I've always liked Berbatov," he said. "I wanted to buy him when I was the coach of Ajax and he was at Bayer Leverkusen.”
It was at Leverkusen where Berbatov first rose to European prominence, scoring five Champions League goals in the 2004/05 season.
Since his £30 million transfer from Tottenham Hotspur to Old Trafford, United have only found themselves on the losing side once when Berbatov has scored.
However, the forward has yet to find the net in European competition this season.
Nevertheless, Van Gaal is aware that Manchester United can score goals and acknowledges that they are favourites for Wednesday's second leg.
Yet he remains confident the Bavarians can book their place in the Champions League semi-finals, adding that Rooney’s expected absence through injury does not affect his game plan.
"There are a lot of goals being conceded by United but they then score three and are through.
"They have the spirit to do this and Alex Ferguson has ensured this.
"We have already beaten Manchester United with Wayne Rooney anyway, so it does not matter to us whether he plays or not.
"And anyway we don't have to win the game, we only need a draw. But United are still the favourites to go through."
In contrast to United, Bayern enter this game on the back of two wins, winning their top of the table clash with Schalke 2-1 at the weekend to regain top-spot in the Bundesliga.
But they have failed to progress beyond this stage of the Champions league since winning the competition in 2001.
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