About this time of year in 2007 I watched Casey Stoner and his wife Adriana walk out of the back of the pits at Sepang, get into their hire car and drive back to their hotel.

It was 4.30pm and everyone else was still out on track, hunting for a lap time and a setup. I knew then that his rivals were in big trouble. He ended up dominating that year’s World Championship.

This time Stoner didn’t leave the recent season-opening Sepang tests early but he started very late and the result was just as daunting. An old back problem prevented him from doing all but four uncomfortable and slow laps on day one, so his rivals were already a full day ahead when he rode out of the pits on day two. And yet it took him just three laps to set the second fastest time so far.

That is utterly, breathtakingly remarkable. Stoner hadn’t ridden a MotoGP bike since early November and yet it took him only a few minutes to reacclimatise himself to life at 200mph, with a lap time just tenths outside the lap record.

This has always been one of the many glittering weapons in Stoner’s armoury and – even if it won’t specifically win him a race – it leaves his rivals dumbfounded and afraid because it’s something they can’t do. While they work steadily up to speed, looking for some feel from the tyres, Stoner gives it full throttle and leaves his instincts to deal with the consequences.

This otherworldly ability comes from Stoner’s childhood spent on the Aussie dirt track scene when he would ride dozens of races a day, most of them lasting no more than a few minutes. In other words, no time for getting up to speed, just ‘Wide F****** Open’ from the starting gate every time.

Stoner always shrugs off comments about his ability to reach lap record pace straight from the pits. “I learn naturally, it’s not a big deal to do those times so soon,” he says, which must freak out his rivals even more.

The reigning MotoGP World Champion and his Repsol Honda RC213V completed the three days at Sepang almost six tenths ahead of 2010 champ Jorge Lorenzo (Yamaha) and his Repsol Honda team-mate Dani Pedrosa. Stoner did his fastest lap of the tests just second time around on the final morning! Lorenzo’s team-mate Ben Spies closed the session in fourth, a further three tenths down, with Valentino Rossi fifth on Ducati’s ‘90 per cent new’ GP12.

It’s still early days yet but Stoner already looks a strong favourite for retaining his title. The only thing that might trouble him is that back problem, the legacy of a crash from his Aprilia 125 at the 2003 Dutch TT. The injury came back to haunt him on the first morning at Sepang when he was doing his pre-ride stretching exercises – his back fully locked up and he needed immediate treatment from the team physio. Last year the injury caused him difficulties during the Estoril GP and resurfaced on and off for the rest of the season. No doubt Stoner will be visiting a few back specialists before 2012 kicks off for real in Qatar on April 8.

Rossi’s debut on the redesigned Ducati V4 – with conventional aluminium frame replacing the factory’s unique carbon-fibre monocoque – was much awaited and yet at the close of play he was 1.2 seconds off, which is pretty much where he was last season. Rossi nonetheless seemed upbeat because he believes Ducati have sorted much of the front-end woes – “the f****** black hole” – that tormented him throughout 2011.

Ducati mechanic Alex ‘Axle’ Briggs put it like this: “We have problems to solve but the good news is that they are new ones, not old ones”.

Only time will tell if Rossi’s new problems are easier to fix than the old…