MADRID (Reuters) - Fernando Alonso says he is only thinking as far ahead as next season and any extension of his McLaren Formula One contract beyond 2017 will depend on how he feels about the sport.
"I'm 34 and I could go on for more years but it's all about motivation and willingness," the Spaniard told Cadena Ser radio. "I'm just thinking about next year.
"We will see how I feel when the time comes, if I sign a contract extension."
The double world champion, seventh in Sunday's Singapore Grand Prix, said the aim was to fight for the championship next season, when the sport undergoes a major rules revamp.
Former world champions McLaren have not won a race since 2012 and endured a nightmare last season at the start of a new engine partnership with Honda after years with now-dominant Mercedes.
"The hunger is always there. After one year and a half without being close to the podium, I have more motivation. I come out as a lion in every race," said Alonso, who joined from Ferrari at the end of 2014.
Whether he stays or goes could determine the fate of British team mate Jenson Button, who is making way for Belgian Stoffel Vandorne next year but has an option for 2018.
The sport will have wider tyres, new aerodynamics and faster cars in 2017.
"Today's cars are less attractive, more boring than with respect to a few years back," said Alonso. "It's not the Formula One that we knew.
"Next year, with the change of rules, the cars are going to be five seconds faster and I'm hopeful that Formula One will be more attractive for the driver."
The Spaniard, who won his titles with Renault, predicted that this year's battle between Mercedes pair Nico Rosberg and Lewis Hamilton would go down to the wire.
Rosberg won in Singapore to move eight points clear of triple world champion Hamilton, who was Alonso's team mate at McLaren in 2007, with six races remaining.
"It's going to go be close until the end," said Alonso. "The reliability of the car will be key."
The Spaniard said McLaren were stepping up the pace.
"Just 12 months ago, we left Singapore with the two cars having abandoned the race," he said. "The line that we have followed since has been tremendously good and it's up to us now to continue to work until next March to keep it up."
(Reporting by Adriana Garcia, editing by Alan Baldwin)