By Ian Ransom

RIO DE JANEIRO (Reuters) - Ku Bon-chan outlasted Frenchman Jean-Charles Valladont in the final of the men's individual archery on Friday to capture his second gold of the Rio Olympics and ensure South Korea completed an unprecedented sweep of all four titles.

The world number two, who won the men's team gold with South Korea on Saturday, survived two nail-biting tiebreaks in the quarter and semi-finals before fending off a hard-charging Valladont to win 7-3 on another gusty day at the Sambadrome.

"Korea has been doing really good so far, but this is a big step further," Ku told reporters after parading around the archery range with a big Korean flag.

"This will be a stepping stone for Korean archery to further improve in the future."

Valladont clinched France's first archery medal since Sebastien Flute's gold at the 1992 Barcelona Games after American Brady Ellison, edged by Ku in a thrilling semi-final, won his second medal of the Games by defeating Dutchman Sjef Van den Berg in the bronze playoff.

Ku's win capped a brilliant tournament for the 23-year-old, who will be feted in his archery-mad nation for his outsized role in securing the sweep.

He sparkled in the men's team final, notching perfect scores of 10 with all six of his arrows to see off a powerful United States team.

On Friday, it was his unwavering composure that dazzled, as he prevailed in two tense single-arrow shoot-offs in succession against Australia's Taylor Worth and Ellison.

With compatriots Kim Woo-jin and Lee Seung-yun eliminated before the semi-finals, Ku entered the title-decider weighed down with the expectations of 50 million Koreans.

"That was another big (feeling of) pressure on myself, so I trusted myself every step of the way and I think that led to the big victory today," he said.

With animated coach Park Chae-sun barking instructions and thumping his chest between arrows, a fired-up Ku led off the final by piercing the inner gold circle for three successive 10's and stormed to a 4-0 lead before world number four Valladont had barely exhaled.

Sensing the match slipping away, the Frenchman raised his game, clawing back to within 5-3, but he crumbled in the decisive fifth set.

Needing a seven to close out the match, Ku thumped it into the eight ring to raise thunderous cheers from ecstatic Korean fans. Valladont bit his lip and stared.

South Korea finished the tournament with five out of 12 medals. The archery superpower has now hogged 23 of the 40 titles contested since the sport returned to the Games in its modern format in 1972.

(Editing by Toby Davis and Meredith Mazzilli)