Sir Jackie Stewart said it was "terrific" to watch Lewis Hamilton match his record of three Formula One world championships in Texas on Sunday.
Sir Jackie, the only other Briton with three titles, won the championship in 1969, 1971 and 1973 and backed Hamilton to go on to further success.
The 76-year-old Scot delayed his departure from the Austin circuit so he could congratulate Hamilton in person after his historic win.
He told ITV News: "It's been a long, long time waiting to see somebody else coming along and consistently winning and Lewis has done that this season in tremendous fashion.
"He himself has driven extremely well this year and I doubt think there's any doubt that right now he's the fastest grand prix driver racing at the moment.
"He's won three now and I'm sure he's going to go on and win more."
Lewis Hamilton's fellow drivers joined the thousands of people around the globe congratulating him on winning his third Formula One world championship.
Former teammate and double title-winner Fernando Alonso, 1992 champion Nigel Mansell and fellow Brit Will Stevens were among those to tweet their support.
Congratulations to @lewishamilton on the championship! Really strong performance and well deserved!! ????????
Congratulations to Mercs and Lewis wonderful finish for US Grand Prix great Champion .Congrats to all drivers today
Lewis Hamilton said equaling his boyhood hero Ayrton Senna's tally of three Formula One world titles made Sunday's championship victory his best yet.
The Brit, who clinched the title with a dramatic victory in Texas, said there was no one else in the sport he wanted to equal or emulate now he had matched Senna's record.
Hamilton, 30, won his first championship with McLaren in Brazil in 2008 after overtaking Timo Glock on the last corner of the last lap. His second came in Abu Dhabi last year after a season-long battle with Mercedes teammate Nico Rosberg.
"The first I won 17 seconds before the end of the race, and obviously last year it was amazing but it took a lot out of us," said Hamilton. "This one still feels just as special, if not more special. I think this has to have topped last year for me, being as it's equalling Ayrton.
"For me it was always to get the three that Ayrton had. He wasn't from the same country as me but he was the guy that inspired me as a youngster. Now I'm like 'I don't know where it's going next'. There is no-one else I look to, that I want to equal or emulate now.
"I feel like I've got the baton now for myself and Ayrton and I'm going to carry it as far as I can, as strong as I can and keep building and see where I take it."
Nico Rosberg appeared to lose his cool after Lewis Hamilton clinched the Formula One world championship, throwing a cap at his Mercedes teammate in the podium room.
Hamilton, who won his third title with victory in Austin on Sunday, threw the cap for second place to the German, who seemed to misinterpret the gesture and hurled it back at the Brit.
On the podium, Rosberg seemed equally glum, refusing to take part in the champagne celebrations.
The pair banged wheels at the first corner during an eventful race and Rosberg lost the lead to Hamilton seven laps from the end after making a mistake and running off the track.
"Turn One for sure was very aggressive," said Rosberg. "We hit each other, or I would say Lewis came into me, so obviously that's not good."
Lewis Hamilton has won the Formula One world championship title for the third time, after victory at the US Grand Prix in Texas.
The victory in a thrilling race means Hamilton equals Jackie Stewart's record as the most successful British racing driver in history.
The Mercedes driver - who is now the first Brit to win back-to-back titles - came first in the championship's opening race in Australia and has led ever since.
“This is the greatest moment of my life,” the 30-year-old said as he crossed the line.
The celebrations looked set to be postponed with Nico Rosberg leading until an unforced error seven laps from the end allowed Hamilton to take the lead.
Following the victory, Hamilton hurled his trophy in the air then caught it again, before being congratulated by Sir Elton John.
Hamilton thanked the crowd for staying in heavy rain to watch his victory, adding: "I think we put a good show on for you today."
Heavy rain in Austin, Texas has caused the US Formula One qualifying to be postponed until Sunday.
Lewis Hamilton could take his third world championship after Sunday's race, if he scores nine points more than Ferrari's Sebastian Vettel and two more than Mercedes team mate Nico Rosberg.
Final practice was run earlier, when the rain was less intense, without spectators being allowed in for safety reasons. Retired triple champion Niki Lauda, now a non-executive chairman for Mercedes, said: "The rain is so hard that no wet tyre can take the cars round safely."
The mayor of Houston said up to 10 inches of rain were expected and weather permitting, the qualifying would resume at 9am local time tomorrow.
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