As recently as two weeks ago, Bernie Ecclestone feared the inaugural Indian grand prix might have to be called off.
The F1 chief executive and other officials have sworn for months that, contrary to eyewitness reports and speculation, the new Buddh circuit would be ready for its late October race date.
But Ecclestone told the Guardian on Saturday:
"I was pessimistic a fortnight ago. I was sent pictures of the track and I thought Christ, we're not going to get it finished in time.
"But what they have done in the meantime - and I've been sent more recent pictures - is incredible."
Added HRT's Indian driver Narain Karthikeyan, who has been in Delhi this week:
"There is still some work being done on the landscaping but everyone is working 24-7 to make sure everything will be fine on the day."
F1 to announce New York street race next week - report
Oct.22 (GMM) News that formula one is coming to New York is back in the headlines.
The Wall Street Journal is reporting on Saturday that the sport will announce next week that a street race in Weehawken and West New York, against the backdrop of the Manhattan skyline, will take place in June 2013.
The report cited "two people familiar with the matter", adding that the press conference will take place in Weehawken, a New Jersey township, at the Hudson River waterside Port Imperial, on Tuesday.
If confirmed, it will mean the United States has two annual grands prix, with Texas set to join the schedule next year at a purpose-built circuit outside Austin.
In August, the Wall Street Journal said the mayors of Weehawken and West New York were in talks with private investors about a 2013 F1 street race.
MotoGP rider killed, F1 safe insists Ecclestone
Bernie Ecclestone is confident formula one remains ahead of the pack in terms of safety.
The F1 chief executive was speaking after the death of Indycar driver Dan Wheldon in Las Vegas last week, and before Italian MotoGP rider Marco Simoncelli was killed on Sunday in a sickening crash at Sepang.
"What a horrible week for our sport," said Team Lotus reserve driver Karun Chandhok late on Sunday.
Added his boss Tony Fernandes on Twitter: "People forget how dangerous a sport racing is."
Ecclestone told the Daily Mail that he is confident this weekend's racing in India will prove F1's safety record, with the sport not recording a driver fatality since 1994.
"In formula one we do everything possible to secure the safety of the drivers and the spectators," he told the Daily Mail.