By Amlan Chakraborty
GREATER NOIDA, India, Oct 27 (Reuters) - Ferrari's Fernando Alonso congratulated Red Bull's Sebastian Vettel on his fourth successive Formula One world title on Sunday but reserved judgement on where the German stood among the greats.
Alonso saw his faint chances of keeping the championship battle alive evaporate when Vettel completed an Indian Grand Prix hat-trick to become Formula One's youngest quadruple champion.
"Congratulations to Sebastian. Obviously a very, very strong season, dominating specially the second part of the year with many many wins. Well done to him and to the team," Alonso, who finished 11th, told reporters.
"Hopefully next year we can make things more difficult."
Alonso went into Sunday's race trailing Vettel by 90 points and the German sealed the championship with the ruthlessness that has become the hallmark of his sustained domination in the past four years.
The 26-year-old's success has left many wondering if Vettel might be the greatest modern Formula One driver but numbers alone would not convince Alonso, who is widely regarded as the sport's most complete driver even if his car is currently inferior.
"Different opinions for different people and all of them we need to respect," Alonso said.
"Many people think Ayrton (Senna) was the best ever. He won only three championships, compared to people who have won more.
"Some people think Michael (Schumacher) is the greatest. If you see the numbers, he should be the best because he has 91 victories, seven titles.
"His (Vettel's) driving performance is big with numbers, being four-times champion. In 2011, I remember him winning 14 or 15 races, this year he will win, I don't know many. Now it's 10, he will win maybe 13 races."
Alonso would not hazard a guess whether he, given an equally fast car, could beat Vettel and preferred to focus on mounting a stiffer challenge next year.
"I'm not here to guess...today is the day to congratulate him and for him to enjoy the championship and it's the day for us to start working even harder.
"They have been very strong, dominating for the last four years. We need to do something better than what we did in the last four years because it's clear that it's not enough. So we will start immediately."
For the time being, Alonso was happy trying to ensure Ferrari finished second in the constructor's championship after being overtaken by Mercedes.
"For me, it makes a difference to have the team happy. They, at the end of the month, pay me...you need to make happy (the person) who gives you food," he said. (Editing by John Mehaffey)