- Novak Djokovic and Petra Kvitova awarded title of ITF world champions for 2011
- World No. 1 Djokovic claimed three grand slam titles during an incredible year
- Kvitova claimed a first grand slam title and also won the WTA Championships
- Bryan brothers won men's doubles award, Kveta Pschke and Kata Srebotnik the women's
The International Tennis Federation honored Novak Djokovic and Petra Kvitova for breakthrough years on Tuesday, as the duo were named the governing body's men's and women's world champions for 2011.
World number one Djokovic began the season with a 43-match winning streak before claiming three of four grand slam titles in 2011.
Kvitova headed off top-ranked Caroline Wozniacki after securing the first grand slam triumph of her career at Wimbledon in July and triumphing at the season-ending WTA Championships in October.
The 21-year-old also helped the Czech Republic win the Fed Cup final against Russia last month as she rose to second in the standings.
The world champions are decided by a system which lends greater weight to grand slam and Fed or Davis Cup success than world rankings or ATP and WTA Tour tournaments.
"I am proud to have been named the ITF world champion for 2011," said Djokovic, who usurped last year's winner Rafael Nadal at the top of the world rankings in July.
"Starting with victory in last year's Davis Cup final, this has been an almost perfect 12 months for me. I have always dreamed about becoming the best in the world, and to have won three grand slam titles and finished the year as No. 1 is very special."
The 24-year-old Serbian clinched the Australian Open, Wimbledon and U.S. Open crowns to become the first player outside of Spaniard Nadal and 16-time grand slam winner Roger Federer to claim the award since American Andy Roddick in 2003.
Kvitova won six WTA titles in a year which saw her rise from 34th in the world rankings.
"I will cherish this award, which is the cherry on top of a wonderful year in which I managed to win Wimbledon, the WTA Championships," she said.
"It was a dream year and something I will never forget."
ITF president Francesco Ricci Bitti added: "Both Novak Djokovic and Petra Kvitova have managed to combine strong performances for their country with outstanding individual records.
"Novak's achievements this year are remarkable in such a strong era for men's tennis, while Petra has made a major breakthrough on the women's tour."
American twins Bob and Mike Bryan won the men's doubles award for the eighth time in nine years after a season in which they lifted the Australian Open and Wimbledon trophies.
Those victories brought the 33-year-olds level with Mark Woodforde and Tood Woodbridge's Open era record of 11 grand slam titles, and they have now broken John McEnroe's record of 270 weeks as the top-ranked doubles player.
Kvitova's Fed Cup teammate Kveta Peschke, 36, and Slovenia's Katarina Srebotnik, 30, won the women's doubles honor after claiming their first grand slam title at Wimbledon.
The duo, ranked second and third respectively behind Liezel Huber, won six other events.