08/09/2016 13:31 EDT | Updated 08/10/2017 01:12 EDT

Phelps, Ledecky, Lochte: Star power on display in Rio

RIO DE JANEIRO — Plenty of illuminating star power for the Rio Games on Tuesday.

Michael Phelps, Katie Ledecky and Ryan Lochte are in the pool. Simone Biles and the American women's gymnastics team are on the mat and the Brazilian women's soccer team will try to pick up the slack for the celebrated men, who have underwhelmed early in the Olympics.

Lochte swam the anchor leg of the 4x200-meter relay, helping the Americans to a comfortable victory in their preliminary heat with a time of 7 minutes, 6.74 seconds. Things didn't go so well for the American men in rugby sevens when Argentina scored in the closing seconds for a 17-14 victory.

Later on Tuesday, Phelps looks to win gold medal No. 20 when he swims in the 200-meter butterfly against South African Chad le Clos, who beat Phelps in London; the U.S. women's gymnastics team goes for gold in the team competition; and Lochte is set to make his Rio debut in the preliminaries of the men's 4x200-meter relay.

The 200-meter butterfly is what Phelps does best, but he mistimed his finish in London, allowing le Clos to edge im at the line. It didn't sit well with the American superstar, who got off to a rousing start to the Rio Games by leading the 4x100 freestyle team to gold.

"Should be a fun race," Phelps said.

Le Clos is ready, too.

"May the best man win," he said. "I'll race my heart out."

Other highlights from Day 4 of the Rio Games:

CORONATION TIME: Biles and her American gymnastics teammates have been head and shoulders above the competition during qualifying. They posted the top score by 10 points, an enormous gap in the world of gymnastics scoring. Now the question may not be if the Americans will win the gold but by how much. But national team co-ordinator Martha Karolyi isn't taking anything for granted.

RUGBY STUNNER : Sonny Bill Williams was helped off the field with an injured left ankle during New Zealand's shocking 14-12 loss to Japan in its first game of rugby sevens at the Olympics. The 12-time world series champions and one of the leading contenders for the first rugby medals awarded at an Olympics in 92 years, the New Zealanders struggled against the high-energy team from Japan.

BRAZIL'S HERO: While Neymar has been a disappointment for the wildly popular Brazilian men's soccer team, Marta has been a revelation. Marta Vieira da Silva has toiled in the shadow of the men for most of her career, but playing in front of her home fans in the Olympics has given her the chance to shine. She had two goals in a victory over Sweden on Sunday and is back Tuesday night against South Africa.

JUDO HISTORY : Hungarian-born Szandra Szogedi made history when she stepped onto the judo mat. Except that it was for Ghana. Szogedi became the first female judoka to represent the African nation, after obtaining Ghanaian citizenship through her husband. Facing Brazilian Mariana Silva in the first round, Szogedi, also had to deal with a very partisan crowd shouting support for her opponent. After less than two minutes, however, the fight was over: Silva took Szogedi down and caught her in a stranglehold. After the fight, a tearful Szogedi said she was "gutted" and that training four years for so little time on the mat was devastating.

ADRIAN SQUEAKS IN: Defending Olympic champion Nathan Adrian narrowly advanced in the 100-meter freestyle, grabbing the 16th and last spot for Tuesday night's semifinals with a time of 48.58 seconds. He was 0.68 seconds behind top qualifier Kyle Chalmers of Australia, who was timed in 47.90. The other American, Caeleb Dressel, was second fastest in 47.91.