KRASNAYA POLYANA, Russia -- Kaillie Humphries arrived at the start house for her final bobsled run at the Sochi Games not knowing how much time she needed to make up to catch the leaders.

Her brakeman, Heather Moyse, knew but wasn't saying. She wanted her pilot to worry about her own run and not the clock.

"I just looked at her and I said, 'It's possible,"' Moyse said. "That's all Kaillie needed to know, that the gap wasn't closed but it was possible."

Humphries visualized the 17-turn track in her mind and set out to nail another consistent run. She delivered just that Wednesday night and it was enough to give them a second straight Olympic title.

"When I don't know times, I mean ignorance is bliss," Humphries said.

The Canada 1 sled had a gap of 11-100ths of a second to close entering the final run. Moyse delivered with a strong push at the start, then Humphries took over from there.

Both were elated at the finish and satisfied knowing they did everything they could.

"For both of us to know we pushed the hardest we could have possibly pushed, I drove the track the very best that I knew how, when we got out of the sled on that fourth run both her and I -- without even having to really say anything -- knew that we had done everything in our power," Humphries said.

With at least a silver locked up, they had a nervous two-minute wait in the finish area as Elana Meyers and Lauryn Williams completed their final run.

"I never wish bad on people but I was thinking, 'Just make a few mistakes, please,' " Humphries said.

The pressure seemed to get to the Americans, who had a few wobbles down the Sanki Sliding Center track and came up one-10th of a second short.

It would be gold once again for the Canadians, who were underdogs when they won at the Vancouver Games four years ago but favourites this time around.

"It's different," Humphries said. "Winning in Vancouver, being at home, first Olympic gold for us -- that was a dream come true. But to be able to do it again and to be able to defend, it's less about a fluke and more that our plan and process and who we are as people really make the difference.

"That's a really great feeling."

Humphries edged Meyers -- her friend and occasional training partner -- by just one point for the World Cup overall title this season. They quickly showed they were the pilots to beat with impressive runs Tuesday.

"I don't think I've ever seen anything like it, that nip and tuck between two people for four runs," said Canadian coach Tom De La Hunty. "It was great."

The Americans set a track record and a start record on the opening day of competition but couldn't deliver in the finale.

Humphries, from Calgary, and Moyse, from Summerside, P.E.I., finished with a four-run time of three minutes 50.61 seconds. Meyers and Williams were second in 3:50.71.

"She put down four absolutely consistent runs and that's the mark of the girl," De La Hunty said of Humphries. "She was able to do it under enormous pressure and the other girl, Elana, wasn't able to do it."

The United States also won bronze, with Jamie Greubel and Aja Evans finishing a full second off the lead in 3:51.61. Edmonton's Jenny Ciochetti and Chelsea Valois of Zenon Park, Sask., were 13th in the Canada 2 sled in 3:54.49.

Moyse took a break from the sport before this season and returned to top form right away, setting a push record in Calgary before winning her first World Cup race back with Humphries at Canada Olympic Park.

They had a solid season and were ready to peak at the right time. The Canadians felt that consistency -- not a comeback -- won them the gold this time.

"Kaillie is so good at handling pressure and so consistent, that she does what she does and lets the field move around her," said former teammate Helen Upperton. "And that's what happened."

Moyse and Humphries jumped up and down, hugged each other and ran to the spectator area to hug family members and friends in the first row.

They had achieved their goal of being the first women's bobsled duo to win back-to-back Olympic titles and it was time to celebrate.

"They executed perfectly," said Upperton. "It's what you expect from somebody that's an Olympic champion."