By Ian Ransom
MELBOURNE (Reuters) - Lewis Hamilton spent the off-season crisscrossing the globe to party with A-list celebrities but Formula One's reigning champion is adamant there will be no hangover when he returns to work at this week's season-opening Australian Grand Prix.
The clear bookmakers' favorite to win a third successive title with Mercedes, Hamilton will arrive in Melbourne after a whirlwind trip to New Zealand where he took to the skies in a helicopter on Wednesday above the mountain resort of Queenstown.
Hamilton's frequent flying and party lifestyle prompted some pundits to voice concerns about his focus and energy levels in the leadup to Sunday's race at Albert Park.
However, the 31-year-old says his competitive drive remains as sharp as ever and his feet will be firmly on the ground once he enters the paddock.
"I know there's still more to come from me -- I think I've shown that in the past two years," Hamilton, winner in Australia last year and in 2008, said this week.
"There certainly needs to be some extra in my tank, as the competition will be stronger than ever this year."
Many invested in motor sport's pinnacle series will hope Hamilton is right about the level of competition he expects to face this season.
Another win in Melbourne from pole position for the Briton could add more voices to the growing weariness of the Silver Arrows' dominance.
The constructors champions are bullish about their car after near-flawless pre-season testing, however, and team mate Nico Rosberg may again loom as Hamilton's stiffest competition in Melbourne.
While Hamilton has been living life like there is no tomorrow, there is also a sense that time is running out for his German rival, whose Mercedes contract expires at the end of the season.
After Hamilton wrapped up his third title in Texas last year, Rosberg closed out the season with three successive wins, and at Albert Park he will hope to prove the late flourish owed more to his racing than a dip in his team mate's motivation.
Ferrari, fired by four-time champion Sebastian Vettel, were the only team to deny the Mercedes' drivers a sweep of race wins last year and the new SF16-H car showed impressive speed during testing.
With only 11 cars finishing last year's season-opener in Melbourne, however, reliability will be paramount and that quality alone may be enough to score points.
F1 bosses will hope Melbourne can lift the off-season gloom that has hung over a series which drivers have criticized for being over-complicated by rule changes and which commercial supremo Bernie Ecclestone said he would not even bother taking his family to see.
A positive start by Haas, the first U.S.-owned outfit in 30 years, would help, and the new team will look to upstage more seasoned rivals like Sauber, who have the same Ferrari engine.
Indonesia's first F1 driver Rio Haryanto will also add a novelty factor when he debuts for Manor Racing.
He is among three rookies set to make their race debuts, along with German team mate Pascal Wehrlein and Britain's Jolyon Palmer at Renault.
Along with the new drivers, F1's governing body will feel some butterflies with the debut of a new qualifying format which sees drivers progressively eliminated during the three phases rather than knocked out at the end of each of them.
Introduced to make F1 more exciting but approved less than two weeks ago, the new format has been slammed by drivers.
"I'm personally not a fan ... and I think, speaking on behalf of all the drivers, no driver is," Vettel told Sky Sport.
(Editing by Peter Rutherford)