US Open semi-finalist Shelton of the United States put Team World on the path to a 4-0 lead with a 7-6(4), 6-1 victory over Team Europe's Arthur Fils of France.

Argentina's Cerundolo followed with a 6-3, 7-5 victory over Alejandro Davidovich Fokina of Spain - the first time that Team World had led after the opening session of the team tennis event.

Auger-Aliassime, whose Sunday singles win over Novak Djokovic was key to Team World's win last year, opened the night session with a 6-4, 6-3 win over French veteran Monfils, whose lighthearted approach to the contest rubbed the Canadian the wrong way.

Auger-Aliassime was irked when Monfils briefly took a seat near a line judge rather than preparing to receive serve, pointedly asking the umpire if he planned to enforce competitive match rules.

An underhand serve from Monfils didn't improve Auger-Aliassime's mood. The Canadian's complaints seemed to send Monfils into a spiral that saw him surrender the opening set with a service break that featured a double fault and three forehand errors.

Monfils pulled himself together to give himself a triple break chance in the opening game of the second set. He couldn't capitalise, however, and once Auger-Aliassime broke him in the second game the Canadian was able to cruise home, the two exchanging a hug when it was all over.

"Things get tense on the court sometimes," Auger-Aliassime said of his heated exchanges with Monfils on a couple of first-set changeovers.

"Only one guy gets the win in the end, so you try your best to stay cool but at the same time to stand up for yourself.

"That's what I was trying to do, get the energy going and just try to not let him take too much ground, I guess."

The day started with a strong showing from Shelton, the 20-year-old whose sensational run to the US Open last four saw him rise to 19th in the world.

Fils, a 19-year-old who earned his first ATP title at Lyon in May, led the first-set tiebreaker 4-1, but Shelton won six straight points to pocket the set and grabbed a 3-1 lead in the second with the first service break of the contest.

Guns blazing

As Fils's unforced errors mounted, Shelton broke again for a 5-1 lead and served it out with aplomb.

"I really wanted to be able to set the tone with my energy for Team World today," Shelton said. "I think it went pretty well."

Cerundolo then closed out a see-saw battle with Davidovich Fokina, which featured seven breaks of serve in the second set.

Broken as he served for the match at 5-4, Cerundolo broke back and closed it out.

"Obviously we came in with guns blazing," said World captain John McEnroe, whose squad is defending the title for the first time.

Europe won the first four editions of the event that began in 2017, but Team World triumphed last year in London in an edition notable for the farewell doubles appearance by Swiss great Roger Federer alongside long-time rival Rafael Nadal.

Federer was in attendance at Rogers Arena - home of the NHL's Vancouver Canucks - and received a huge ovation as the teams captained by McEnroe and Bjorn Borg were introduced to start the day.

Federer also assisted in the coin toss before the closing doubles match, which Americans Frances Tiafoe and Tommy Paul won for Team World 6-3, 4-6, 10-6 over Fils and Andrey Rublev.

Friday's matches were worth one point each, but the stakes rise at the weekend with Saturday's matches worth two points and Sunday's three.

The first team to reach 13 points wins.