Chelsea reached the quarter-finals of the FA Cup thanks to a treble from Anelka who flourished beside Drogba as assistant coach Ray Wilkins turned to a 4-4-2 formation.

The Blues had been stunned by Tamas Priskin's 69th-minute opening goal and Wilkins, in charge until caretaker coach Guus Hiddink is installed tomorrow, opted to change from the 4-3-3 system he began with.

He replaced midfielder John Mikel Obi with winger Miroslav Stoch and two minutes later Anelka equalised as he and Drogba ran the tiring Watford defence ragged.

Anelka then headed Chelsea in front two minutes later before claiming his 20th of the season in stoppage time.

The France international was often used at the main striker or out on the flanks under former boss Luiz Felipe Scolari.

The Brazilian coach, sacked last Monday, would not deviate from his 4-3-3 system even though it is alleged the players wanted a change to 4-4-2 in order to accommodate Drogba and Anelka.

Drogba, his season interrupted by injury and suspension, was axed by Scolari after their 3-0 defeat by Manchester United last month but Wilkins restored the Ivorian to the starting line-up as the main striker against Watford.

But he was forced to abandon the system when substitute Priskin raced clear of the defence and lifted the ball over Petr Cech to put the struggling Coca-Cola Championship side ahead.

Now the 29-year-old feels they can be a formidable pairing in a 4-4-2 system although much will depend on the plans of new coach Hiddink.

"Didier and I showed that we can play together and score," said Anelka. "The fact that I had Didier by my side changed the match. I had more freedom. When you're all alone up front it's sometimes difficult."

The France international also revealed he has not been happy with his form despite topping the Premier League goal charts with 14 and plundering 20 in all competitions.

"Despite the goals I'm not happy with my performance," he told L'Equipe. "I'm not happy with myself.

"What's important for me is to play well. And I haven't felt I've played well, even when I've scored."

Anelka also believes their win at Watford could be the turning point of the Blues season.

"We have had a difficult period but we showed a lot of character," said Anelka. "The most important thing now is to win games.

"It is always difficult when you change the manager. We had a strange period when we had a lot of chances but could not score.

"But I hope we have reversed everything and now we will win a lot of games in the league.

"We deserved to win. We wanted to win. We knew we were capable of doing it. Obviously the new manager was in the stadium but it was good to come back in a winning way.

"In the last one or two months we have had a lot of chances but the ball didn't want to go in. We had a lot chances against Watford but when you stay focused and you have a lot of big players in the team, you know you can score.

"We have a big team, big players, and even when we were losing 1-0 we knew we had the capability to win the game."

Chelsea now go to Aston Villa in the Barclays Premier League next weekend knowing they must win to keep their title hopes alive.

Villa are third in the table and two points ahead of the Blues but Anelka is confident Chelsea can claim a crucial away success in Hiddink's first game in charge.

"The Aston Villa game next week is massive because they are in front of us," said Anelka.

"If we are still to be in chase for the Premier League we have win. We will go there to win. It is going to be tough but I think we have a lot of big players and we can do it."

Hiddink watched from the stands at Vicarage Road and officially starts work with the squad tomorrow. It is something the Chelsea players are already excited about.

"We know him as a manager and what he has done before with a lot of teams," added Anelka. "We look forward to working with him."