Jorge Lorenzo has a perfect record at Estoril, winning from pole at all three of his previous MotoGP appearances - and the world champion returns in 2011 holding the early points lead.
"This week we will be in Portugal, a country where I've had nice moments!” said Lorenzo, who holds a nine point lead over Repsol Honda's Dani Pedrosa after 2-1 finishes so far this season.
“In Estoril I got my first victory in the MotoGP class in 2008 which I repeated over the last two seasons. The track has turned into a talisman for me and it is the place where the astronaut always comes back," he added, referring to his special livery.
“We have been training for a month, and I hope that this makes us fit for a good race. We are in front of the standings, but it is very early and it is just the beginning.”
Lorenzo is rumoured to be getting a new M1 engine to try in the post-race test on Monday, having complained of a power deficit since winter testing.
“This week will also be important since we are testing on Monday and we will certainly be able to check a lot of things for the future set-up,” he said.
In contrast to Lorenzo's enviable Estoril record, new Factory Yamaha team-mate Ben Spies is yet to start a Portuguese Grand Prix, after crashing and being injured on the way to the grid for the October 2010 event.
Spies also crashed out of the wet race at Jerez earlier this month, while on target for second place, and can't wait to get back on track.
“Although I've enjoyed the opportunity to head home and get some chill out time in Texas this break has been way to long for me,” said Spies. “The team worked really hard over the weekend in Jerez and by race day had delivered a competitive set-up that meant we could fight for the podium. Unfortunately it wasn't to be.
“I really enjoyed the first practice sessions here last year and was frustrated to have not made the race, I can't wait to get started on Friday morning and see what we can do.”
Spies had been due to start fifth in last year's race, which saw wet practice, then qualifying abandoned, before a dry race.