Ducati's Casey Stoner destroyed any doubts about his speed, commitment or fitness - following a three round MotoGP absence to treat fatigue problems - by finishing a strong second in Sunday's Portuguese Grand Prix at Estoril.

It was the Australian's best result since victory at round five in Mugello, the last race before he was struck down by a mystery illness, the physical effects of which haunted the 2007 world champion for five races before he took the decision to step out of the championship.

Despite a non-stop series of medical tests during his break, a single definitive cause of Stoner's exhaustion wasn't pinpointed - although low blood pressure levels and a lack of sodium were found - and it was therefore far from certain that the symptoms would not return in Sunday's race.

Fortunately, having already proven that his raw speed was a strong as ever with third in qualifying, the 23-year-old eradicated any doubts about his motivation or love of racing by forcing his way past Colin Edwards, world champion Valentino Rossi and then Dani Pedrosa within the first two laps.

That left just his physical strength in question and, although the 18 time MotoGP race winner couldn't keep pace with race leader Jorge Lorenzo, he said it was his decision to back off a little - and he was more than a match for the rest of the field.

Stoner crossed the finish line 6.3sec from victory, but 3.6sec ahead of Pedrosa's Honda and a huge 17 seconds in front of a struggling Rossi to claim his first podium since round seven at Assen.

"We couldn't be happier today," declared Stoner. "Jorge rode a fantastic race. We weren't going to be able to chase him down easily. It would have been past the limit so my hat off to him. But for us to come back and do this in front of everyone, after what everyone had said, is a big relief for me and a nice feeling."

The 23-year-old was beaming with delight as he celebrated with his Ducati team in parc ferme, having felt only 'normal' tiredness, due to a lack of training, during the 28 lap race.

"As you can see I can walk, I can talk and I feel pretty good!" smiled Stoner after the podium ceremony. "There were so many people sitting there saying it was all in my head, all a big show or whatever.

"They didn't understand how sick I was after those races. To finish a race like today - even after qualifying yesterday we knew the problem was gone. I was doing more laps than I ever was before and feeling perfect after it.

"I think it almost means more to Ducati than me, after all the criticism they've taken. Everyone saying there was conflict in the team or whatever. People should realise by now the relationship I have with Ducati, grow up a little bit and see that a few races away isn't going to change that."

Stoner also hit back at Kevin Schwantz, saying he had 'lost respect' for the 1993 world champion after the American appeared to criticise him for pulling out.

"I've lost a lot of respect for Kevin Schwantz," said Stoner. "He was one of my favourite riders and one of the most exciting to watch. But saying something like that [without knowing the full circumstances] just shows that experience counts for nothing."

To put Stoner's Estoril performance into perspective, it was the closest he has been to victory since the 'official' start of his illness at Barcelona, having finished +8.884sec (Catalunya), +23.113sec (Assen), +12.432sec (Laguna Seca), +10.226sec (Sachsenring) and +1 lap (Donington, wrong tyres) during his five 'sick' races.

However, Stoner revealed that the first signs of illness may have been present from round three.

"Not only has it been a long time off the podium, it's been a long time since we were competitive," said Stoner. "Even before Catalunya we realised, after we sat down and thought about it, that things were becoming more difficult.

"Jerez [round three] was becoming physically difficult and then Le Mans and Mugello were 50/50 [wet/dry] which covered up a lot of problems. Then from Catalunya onwards I had a lot of dramas.

"It was nice to know we can be competitive to the end of the race now. Today we knew when to give up. We were pulling a gap on Dani, we had plenty left in the tank, but Jorge was either keeping his advantage or slowing pulling out. That was pretty much it for me. I had put as much into it as I thought I should."

Stoner's early hard-riding did however claim one casualty - his footpeg!

"Earlier in the race I would have been a little bit faster accept I made a mistake going through the right kink. My foot came off and I snapped my footrest so it folded up out of the way," he revealed. "Going into right hand turns it kept folding up, folding up. It was a little bit of a pain, but I sorted it out towards the end of the race and I didn't really go any faster - so maybe it wasn't a problem!"

Round 15 of the 2009 world championship will be Stoner's home Australian Grand Prix, on October 18.

"I'm looking forward to using this next week to train a little bit," said the #27. "Basically we tried to cut all that away to let my body recover from whatever it is and build up whatever I'm lacking in all the blood tests. We did the best job we could and came back pretty strong here but I still need to get muscles and everything working again so this next week we'll be out in the gym and out on the [push] bike getting some miles in.

"The target for the next few races is for myself and the team to prepare as well as we can for next season," he concluded.

"We're happy more than anything to see Casey with a smile back on his face - before, during and after the race weekend," said Ducati Corse general director Filippo Preziosi.

The next best Ducati rider after Stoner was factory team-mate Nicky Hayden, who finished 32.5sec behind the Australian in eighth.