WATCH | Extraordinary scenes as Davis Cup tennis player knocks down opponent, then wins by default

Belgium secured a controversial victory in Davis Cup qualifying when Chile's Cristian Garin refused to continue in the decisive rubber after being painfully knocked down by his opponent, Zizou Bergs, on Sunday.

READ | Henning digs deep to steer SA to Davis Cup victory over Nigeria

Elsewhere, Spain made light of the absence of Carlos Alcaraz as they swept past Switzerland.

France also advanced and Hungary survived a second-day fightback by Canada.

In Hasselt, after Belgium won the day's opening doubles to lead 2-1, Bergs then faced Garin in the first reverse singles.

After holding serve in a marathon 11th game in the third set, an excited Bergs galloped 'round the court in celebration and raced past the net towards his chair, colliding with Garin and sending him flying.

"It's truly unintentional," Bergs said. "I wanted to go fast to the bench, but I made a completely wrong decision to not wait for the opponent."

Zizou Bergs makes a HUGE shot to break serve... but accidently collides with Cristian Garin in celebration ?? pic.twitter.com/6H2RqRmx4m

An independent doctor ruled Garin was fit to continue and serve to stay in the match, but he refused. Bergs was awarded the deciding game to win 6-3, 4-6, 7-5.

"It feels really bad to end this way," Bergs told the Davis Cup website. "It's obviously not what you want, to hurt an opponent."

Bergs said he also apologised to Chile captain Nicolas Massu.

"Terrible situation," said Massu. "We're here to play tennis, to defend our country. Garin is the player hit in the eye, who couldn't continue and now we're out."

An ITF spokesperson said: "We understand the emotions attached to this unusual incident, but the final decision was made after consideration of all the facts and unique circumstances