It was another easy win for
The Serb's celebrations at the
"Being No. 1 of the world is the pinnacle of the sport," said the 27-year-old Djokovic.
"One of the highest and most difficult challenges is to be No. 1 nowadays, especially because the tennis has become very competitive in the last five, ten years, very physical. To have a shot at No. 1 of the world, you need to be consistently healthy and successful throughout the year."
Berdych dropped his first two service games as the Serb took control from the baseline. Djokovic again broke twice in the second set with a range of forehand winners, powerful returns and net charges that frequently left Berdych stranded.
"I believe everything happens for a reason. So I'm here for a reason, and I managed to finish the year as No. 1 for a reason," he said.
Djokovic and Federer have swept their groups in London, and are on course to meet in Sunday's final. After enduring one of his worst seasons last year, Federer is back to his best and proved to be a worthy challenger in their battle for supremacy.
"Roger is playing some of his best tennis since I know him and since I watch him," said Djokovic. "We played an amazing final of Wimbledon. We fought all the way through basically the last few days of the season for No. 1. That proves how good he played over the course of 12 months."
Before a mouth-watering potential showdown, Djokovic will first take on
Djokovic has been in supreme form since the birth of his first child, Stefan, on Oct. 21, and has won 16 of his last 17 matches. In London, he extended his two-year-old indoor winning streak to 30 matches and has lost only nine games this week.
"I think I had a great season and a great year overall for my private life and professional, as well," he said. "Considering all the things that have happened and circumstances, I thought I have done very well."
Besides winning his seventh Grand Slam title at the All England Club, Djokovic was also runner-up at the
Before taking some time off, he now has two more matches to win to claim a fourth title at the Finals and become the first player since Ivan Lendl from 1985-87 to win the elite tournament three years in a row.
Because of the formula used to determine the group standings, Wawrinka needed only to win three games against Cilic to finish second in his group and book a spot in the semifinals for the second consecutive year.
Cilic broke Wawrinka at love in the 10th game of the second set to even the score and built on the momentum to move 2-0 up in the decider.
But the hard-hitting Croatian failed to hold press home his advantage, allowing Wawrinka to break back. Cilic later dropped his serve following three consecutive unforced errors to hand his opponent a 4-3 lead.