Tennis: Djokovic restarts by beating a friend

World number one Novak Djokovic did not let friendship prevent him from carrying on where he left off last month when he made a successful defence of his Australian Open title at the Dubai Open here on Tuesday.

Djokovic's attempt to win back the Dubai Open title began with a 6-1, 6-4 win over Viktor Troicki, the fellow Davis Cup player with whom he grew up and shared tennis courts many times in the city of Belgrade.

The top-seeded Serbian moved so swiftly and turned defence into attack so suddenly that it was hard to believe four weeks had passed since he last played singles on the ATP tour.

The only blemish in Djokovic's performance was letting slip an early break of serve in the second set, when he delivered a moderate second serve and missed with a backhand drive to allow Troicki back to 4-4.

But he intensified his focus and broke again immediately, with some resilient containing and counter-attacking, and then closed out the match without fuss.

"Because I have not played for a while I was extremely focussed and committed to starting well," Djokovic said.

"I played really, really well in the first set. I read his serve well, and I was aggressive in the court.

"So altogether I am satisfied with my performance and I hope I can continue," he concluded. That will be against Roberto Bautista Agut, the world number 55 from Spain.

Earlier Djokovic was asked if he might be starting on another long unbeaten streak, as he had the season before last.

"Yes I am definitely am (on a streak)," he said.

"But I am not thinking about it or trying to better the one I had in 2011, because it's really hard to ask from myself something which may be impossible.

"But knowing that I have done it gives me that mental edge and confidence I need in to approach every tournament with self-belief."

Djokovic should have a semi-final against Juan Martin Del Potro, the former US Open champion, although the Argentinian nearly did not survive beyond the first round.

Del Potro had to save four match points to beat Marcos Baghdatis, the former Australian Open finalist from Cyprus, by 4-6, 6-4, 7-6 (7/4).

Baghdatis, ranked 36, got his chances as Del Potro was serving at 4-5 in the final set, when the seeded player went 15-40 and then advantage point down.

On the first two match points Baghdatis was a little passive, allowing Del Potro to work his way out of difficulty, and on the third Del Potro launched a good first serve and a fine follow up forehand.

Nikolay Davydenko, who hopes to return to the top 20 this year as part of his farewell to the tour, reached the second round too, the former world number three from Russia beating Janko Tipsarevic, the sixth-seeded Serbian, 6-0, 7-5.

But Jo-Wilfried Tsonga, the fifth-seeded Frenchman, was beaten by his Davis Cup team mate, Michael Llodra.

Tsonga was back on court less than 48 hours after winning in Marseille, and more than 3,000 miles away, with depleted energy, and, as the match wore on, declining motivation too.

Tsonga expressed annoyance with a replayed point after a disputed line decision on a serve in the seventh game, when Llodra broke back.

"My first serve was in, and the line judge said, out," Tsonga said.

"But he said, out, after the hit. Michael hit the ball back, you know, but into the stands. And the umpire said, replay the point, but the ball was good."