The Americans teamed up to beat Karol Kucera and Daniela Hantuchova 6-2, 6-3 in the decisive mixed doubles after Kucera had earlier hauled the Slovaks level by beating Blake in a thriller at the Burswood Dome.
The U.S. victory puts Blake's name in the tournament's record books as the only man to have won the Cup twice -- last year he partnered Serena Williams to the silverware.
"Well, again that's a pretty good way to start my year," smiled Blake, as he collected a cheque for A$120,000 and a diamond-encrusted gold and silver year.
"As long as I keep being invited, I am gonna keep coming... this is real fun. And thanks to Lindsay. It is great, I come down here and my partners never lose. It makes my job a heck of a lot easier."
Chanda Rubin and Justin Gimelstob in 1997 provided the other U.S. triumph.
Kucera had earlier made a mammoth effort to claw the unlikely finalists back into the Hopman Cup reckoning when he beat Blake 4-6, 6-4, 7-6 to level the tie 1-1
LITTLE LEFT
But they had little left in the clincher as the American duo romped through the mixed, both Blake and Davenport serve and volleying with panache.
"Congratulations to the great American team for winning this title again," Hantuchova said. "They didn't give us much of a chance there in the mixed."
The Slovaks only reached the final after the already-qualified Australian team had to pull out following an injury to Alicia Molik, and were powerless to hold off the American onslaught.
Davenport's pre-Australian Open stock rose further after her match against Hantuchova during which she swatted aside the slight Slovak 6-3, 6-1.
The three-times Grand Slam champion's form has improved with each match in the Western Australian city and on Saturday she was irresistible.
Not only was Davenport powerful, but she was deadly accurate and made no unforced errors throughout the 51 minute match.