Tomas Berdych feels he needs to improve in several areas if he is to challenge the world's leading players for tennis' top titles next season.

The Czech was beaten in straight sets by world number one Novak Djokovic on Thursday in the final match in Group Stan Smith at the ATP World Tour Finals event in London.

Following the 6-3 7-5 loss, the 30-year-old claimed he has ground to make up but appreciates it will be a difficult task.

"There are certain areas of the game that I definitely need to work on," he admitted.

"No matter if you are five, six, 10 or number one in the world you still have to work on your game and get better and better because the opponents aren't sleeping, they’re trying to improve as well.

"It's definitely one of the aspects that I need to work on or basically be able to get better in those matches playing the top guys.

"I don't know if it's a matter of being more focused or being stronger, whatever part it is. You can call it whatever you want, but it’s a matter of if the ball lands between the lines you can play good tennis."

Berdych was disappointed to see his year's work end on a sour note but is remaining upbeat following his final match of the season.

"Obviously it's not the way I would like to finish the year, it's a bit disappointing not to have any wins here," he said.

"But I think it was a very good and solid year for me, I'm just going to take positives from the season and just keep doing what’s on the plan, working hard and be strong for the next season."

Djokovic's victory sees the Serbian line up a semi-final tie with Rafael Nadal.