A borzoi, pug, bichon frise and border collie will vie for the contest's top prize after winning Monday's group competitions at the 142nd annual Westminster Kennel Club Dog Show.
More than 2,880 dogs from 201 breeds and varieties were set to compete, according to organisers of the United States' second-oldest sporting event.
This year's two-day event in New York City draws challengers from all 50 US states and 16 other countries, including Canada, Mexico, Japan, Russia, Australia and China, the Westminster Kennel Club said.
Individual breeds are judged during the day on Monday and Tuesday, with the winners of each moving on to the group competitions at night. Dogs are divided into seven groups - hound, toy, non-sporting, herding, working, sporting and terrier.
The dogs crowned champion of each of the seven groups then compete for the Best in Show trophy on Tuesday.
Lucy, a borzoi, won the hound group competition on Monday, the fifth borzoi to win in the contest since 1930, according to Westminster Kennel Club data.
"She's just amazing," said Valerie Munes-Atkinson, Lucy's handler from California. "She's always stepped up to the plate and given me 110 per cent every single time. Whether it's freezing, whether it's 100 degrees out, she just goes."
Bill McFadden, the handler of Flynn, who won the non-sporting group contest, said the bichon frise enjoys competing in dog shows and has come to Westminster three times.
"The crowd is so awesome, so loud and so crazy," McFadden said of New York's Madison Square Garden arena where the show takes place. "There's a lot of noise and excitement. The best thing you can do is just hope your dog feeds off it."
McFadden, who lives in California, added that the arena's ring is "difficult".
"The grass is a little pokey on their feet," he said.
Biggie, a pug, and Slick, a border collie, won the toy and herding contests, respectively.
Dogs from the sporting, working and terrier groups will compete on Tuesday night, with the three victors joining Monday's finalists in the competition for top prize.
Rumor, a female German shepherd, was named Best in Show at last year's competition.