Five things to watch at Singapore Grand Prix

Singapore - Championship leader Lewis Hamilton is expecting a "big fight" in Sunday's Singapore Grand Prix with the season suddenly on a knife-edge just as Formula One enters a new era under fresh ownership. Hamilton, whose lead has been slashed to just two points, faces the prospect of a five-pronged assault led by team-mate Nico Rosberg, with the Red Bulls and Ferraris also pushing hard on the twisty street circuit. Apart from the race at the front, here are five talking points ahead of the weekend’s Grand Prix:

1. Wheels of change

Formula One may be undergoing a multi-billion dollar buy-out, but expect more questions than answers as teams and drivers absorb last week's deal. Bernie Ecclestone, who has run F1 for the best part of 40 years, will not even be around to discuss the sale to US billionaire John Malone's Liberty Media group, opting to skip Singapore and stay in London instead.

21st Century Fox vice-chairman Chase Carey, who will become F1's new chairman working alongside Ecclestone, has promised not to “Americanise” a sport which has strong European traditions. But changes are afoot. Ecclestone and Carey are thought to be working towards a 25-race calendar - expanded from a record 21 GPs this year - while Liberty Media will bring some much overdue social media and interactive savvy to a sport whose traditional fanbase faces erosion.

2. Zika bites back

The mosquito-borne disease caused concern ahead of the Rio Olympics and Formula One teams will be on their guard after Singapore was hit by one of the worst outbreaks outside of South America. Several countries including Taiwan and Australia have warned pregnant women against visiting Singapore because of Zika, which is sexually transmissible and can cause babies to be born with abnormally small heads.

Nico Rosberg has consulted Mercedes team doctors and other drivers with young families have also expressed reservations, according to reports. Singapore is not alone, with races still to come in nearby Kuala Lumpur, Mexico and Brazil where there have also been Zika outbreaks. FIA doctors have been advising teams and, despite the extreme heat, long sleeves will be the order of the day for pit lane crews - along with the liberal use of mosquito repellent.

3. Max power

Red Bull's teenage sensation Max Verstappen got a finger-wagging warning from FIA race director Charlie Whiting after his wheel-to-wheel battles bordered on the dangerous in Belgium three weeks ago. But the 18-year-old showed a cooler head in Monza and now believes a second victory of his fledgling career is possible in Singapore.

The winding street circuit should favour the Red Bulls of Verstappen and Daniel Ricciardo with their downforce advantage over the powerful and slick Mercedes. Not only that, an engine upgrade from Renault is due to arrive this week which should give them a power-unit boost. “Singapore is definitely one of my favourites,” Verstappen said. “It's very challenging, not easy to understand and also the heat makes it even harder.”

4. Ferrari gambling on ultrasofts

Sebastian Vettel gave Ferrari their most recent win in Singapore a year ago as Mercedes suffered a mysterious performance meltdown in the hot and humid tropical night race. Ferrari are gambling all out for a repeat victory by opting for the maximum allowed nine sets of the stickiest ultrasoft tyres for each of their drivers.

The 23-turn street circuit places a premium on downforce and mechanical grip, compromising runaway championship leader Mercedes' power and aerodynamic advantage, and giving Ferrari and Red Bull a chance to challenge. It's an aggressive and risky move - Mercedes and Red Bull are taking seven sets of ultrasofts to spread their strategy options - but team boss Maurizio Arrivabene thinks it is worth a shot. “Our best chances I see as Singapore, Suzuka and Austin,” he said.

5. Security on track

Organisers have vowed that security this year will be tighter than ever after a spectator climbed through a gap in a fence and walked onto the circuit mid-race, startling race-leader Sebastian Vettel. “There's a man on the track!” Vettel yelled over the team radio as he hurtled past the intruder at 280km/h. The organisers promised to “fortify the infrastructure and manpower” following an investigation into the incident. The British invader was sentenced to six weeks in prison for “endangering the lives of drivers”.

DRIVER STANDINGS SO FAR

1. Lewis Hamilton (GBR) 250 pts

2. Nico Rosberg (GER) 248

3. Daniel Ricciardo (AUS) 161

4. Sebastian Vettel (GER) 143

5. Kimi Raikkonen (FIN) 136

6. Max Verstappen (NED) 121

7. Valtteri Bottas (FIN) 70

8. Sergio Perez (MEX) 62

9. Nico Hulkenberg (GER) 46

10. Felipe Massa (BRA) 41

11. Fernando Alonso (ESP) 30