MotoGP champion Jorge Lorenzo faces toughest test

Jorge Lorenzo has an ongoing rivalry with fellow rider Valentino Rossi The wraps come off the 2013 MotoGP season in Qatar this weekend with pre-season testing suggesting Jorge Lorenzo has a massive fight on his hands to defend his world championship title .The Spaniard prevailed in a gripping season-long tussle with Dani Pedrosa to claim the 2012 crown in the penultimate race in Australia after his Honda rival crashed out.
Pedrosa, on the speedy and reliable Honda, will be hungry to go one better but Lorenzo faces an arguably greater danger much closer to home.
Nine-time champion Valentino Rossi's decision to end his disastrous Ducati spell and return to Yamaha injects spice to the 2013 campaign given the two riders' stormy past.
Rossi and Lorenzo 'have history' from their previous spell as teammates - their relationship became so toxic at one stage a wall was erected between their two garages to stop the sharing of data.
Yamaha however say the pair are now willing to let bygones be bygones, starting in Doha.
"They are in a completely different moment in their career," Yamaha team manager Wilco Zeelenberg told BBC Sport.
"Three years ago, there was quite some tension there, but at the moment they accept each other very well. Vale is still very fast and Jorge realises that he's a nine-time world champion, so he has to beat him.
"Before, Jorge was the upcoming young guy, but he's become a two-time world champion in MotoGP. Valentino also accepts that Lorenzo is a fast rider and a world champion. That's a big difference compared to 2010."
At testing in Sepang, Rossi said he was set to challenge for the title.
"I can start the championship with the target to fight Lorenzo and Pedrosa," said the 34-year-old Italian, adding that he was inspired "one thousand times more than in the last two years".
And in a sign of the new entente cordiale that has developed between the Yamaha partners, Rossi lavished praise on Lorenzo.
"For me, I think he is perfect. He is very fast in all conditions. He is very fast from the beginning. He never makes mistakes and has a high level of concentration. He is at the top," he said.
Extolling the virtues of unity over divisiveness, Lorenzo, when quizzed on Rossi's return, said: "It is better to work together than to go separately. We are in the same team.
Asked in Malaysia if their relationship would be better second time around the Spaniard added: "Yes, probably something has changed.
"I hope so. I think he hopes so. You can share information. You can speak about the new improvements (that is needed). We must pass some notes. Together is better."
Pedrosa, regarded as favourite for the title by many after going so close in 2012, will be partnered at Honda by 20-year-old Marc Marquez, who arrives in MotoGP as Moto2 champion.
The talented Spaniard replaces Casey Stoner, the Australian former champion who has taken early retirement.