Ben Simmons' Philadelphia 76ers were dominated by the Toronto Raptors in their NBA playoff showdown while Patty Mills almost orchestrated a stunning season-saving comeback for the San Antonio Spurs against the Denver Nuggets.
The Raptors cruised past Philadelphia 108-95 on Sunday (AEST) in Toronto to strike the first blow in the best-of-seven games eastern conference semi-finals.
Three-time All-Star Kawhi Leonard had a career play-off high 45 points, 11 rebounds, two assists and two steals for Toronto.
The forward jumped on the 76ers early, with 27 of his points and seven rebounds coming in the first half.
"They just went down tonight," Leonard said of his shooting touch.
Power forward Pascal Siakam, with 29 points and seven rebounds, was the only other Raptors player to score in double figures.
Melbourne-born Simmons ended the game with 14 points, nine rebounds, three assists and just two turnovers.
He sank seven of his eight field goals but the 76ers – who shot at less than 40 per cent from the field – were no match for the potent Raptors.
Philadelphia coach Brett Brown assigned two of his best defenders, Jimmy Butler and Tobias Harris, on Leonard early but they were unable to control him.
Simmons was the only effective defender on Leonard.
"Personally, I think I did a pretty good job overall, but he's a tough player," Simmons said.
Game two is in Toronto on Tuesday (AEST).
"We're not going away," Brown said. "We'll get better in game two."
The Nuggets eliminated the Spurs in a 90-86 first-round game seven thriller in Denver.
It is the Nuggets' first playoff series win since 2009.
The Spurs appeared headed for a lopsided defeat.
The Nuggets led throughout and were up 53-39 with nine minutes to go in the third quarter when Spurs' coach Gregg Popovich reinserted Mills.
The veteran Australian point guard had a horror shooting series missing 19 of 22 three-point attempts, but he was inspirational on defence in game seven.
The Spurs, led by Mills, whittled down the deficit and with 50 seconds to go only trailed by two points.
The Nuggets, led by Jamal Murray's 23 points and Nikola Jokic's second career play-off triple-double, hung on to survive.
Mills and the Spurs did infuriate Popovich in the final seconds when he screamed at his players to force the Nuggets to shoot free throws by fouling, but they did not follow his order.
Mills had five points and five assists.
The Nuggets will play the Portland Trail Blazers in the western conference semi-finals.