The Cottagers' latest defeat, a 3-0 home loss against Southampton, leaves them lying bottom of the Premier League after several of their rivals recorded victories.
And despite the boost of completing a club-record deal for Olympiakos striker Kostas Mitroglou, former Manchester United coach Meulensteen conceded that Monaco's late bid for Berbatov was unexpected.
"It was [a surprise]," he told reporters. "I kept saying to you all that there hadn't been any offers. It wasn't a last-minute change of mind with Dimitar because there hadn't been any offers.
|12/1||Fulham are 12/1 with Betway to beat Manchester United|
"Obviously the player makes his desire to take the opportunity clear and you can't stand in the way of that.
"That's done, we have added some really good faces ourselves and hopefully they can bring something to the team that will liven the place up."
Meulensteen acknowledged that the job he now faces in guiding Fulham to safety ranks as the most intimidating of his career so far, with the Cottagers travelling to Old Trafford for their next match.
"We can't feel sorry for ourselves," he continued. "We have conceded far too many goals and we have not scored enough goals.
"In the 14 games remaining we have to get [the points] from somewhere and that's what we need to address.
"It's the biggest challenge that I've ever faced in football and I think it's the biggest challenge Fulham have faced in many, many years."
Saints boss Mauricio Pochettino hailed the performances of attacking stars Adam Lallana, Rickie Lambert and Jay Rodriguez, who were all on the scoresheet in front of watching England boss Roy Hodgson.
"If Roy Hodgson was in attendance at the games against Yeovil, Arsenal and today, then he would have seen our strikers scoring goals," he remarked.
"It's very important that they get on the scoresheet. That's always going to increase their chances of making it to the World Cup in Brazil."