Portugal Colonial - Humphries in Olympic monobob driving seat after US switch

Humphries posted a new track record in the first heat of an event making its Games debut, and built up an overnight lead of 1.04sec after the two runs.

That is a huge gap in a sport normally decided by tenths of a second.

The medals will be decided in two final heats on Monday, but the 36-year-old was taking nothing for granted.

"I'm happy with the pushing and the driving, but there is more I can do, I am very aware that anything can happen," said Humphries.

"You have to pretend that today didn't exist and have a fresh race tomorrow -- it's easier said than done.

"I've won and lost from this position."

Humphries won Olympic golds for Canada in the two-woman bobsleigh at both the Vancouver 2010 and Sochi 2014 Games, as well as a bronze four years ago in Pyeongchang.

However she switched to the United States amid allegations she was verbally harassed by staff in the Canadian team. She was sworn in as a US citizen only last December.

"I'm so proud and honoured to be here and to represent the USA, nothing in life is guaranteed," she said.

"It's been step by step, not without a lot of happy moments and tears as well."

Humphries sat out Saturday's final training session, "I'm not a spring chicken any more, I'm competing against 23 year olds -- I needed rest in order to be competitive".

Women’s monobob, where each pilot races alone, is making its Olympic debut at the Yanqing National Sliding Centre.

If she takes gold after Monday's final heats, Humphries will break Germany's monopoly at the sliding centre.

German racers won all of the first six events in Yanqing, with a full house of four wins in luge and two in skeleton.

Germany's Laura Nolte sits in third place, 1.22sec behind Humphries.

"She's a second away, we knew how much experience she brings, but you can easily lose a second in a run," said Nolte, echoing Humphries' sentiment that nothing is decided.

"It's cool to see the others (Germans) do so well, but it also puts on a bit of pressure."

S.Caetano--PC