Defending champion Cleveland and season win leader Golden State, each seeking a third consecutive NBA Finals appearance, are well rested as the second round of the playoffs begins Sunday.
They were the only clubs to advance through the first round without dropping a game and are again favored in their best-of-seven second round matchups.
Cleveland superstar LeBron James, trying to reach the NBA Finals for a seventh consecutive year and eighth overall, led the NBA in minutes played while averaging 26.4 points, 8.7 assists and 8.6 rebounds. He powers the Cavaliers against Toronto, a team they beat in last year's Eastern Conference final.
"Doesn't mean we're going to be able to win this year," James said. "We've got to go out and make it happen. We have to worry about game one first."
Boston faces Washington starting Sunday in the other East matchup, the Celtics having taken the conference top seed over the Cavs.
"The sky is the limit for this team," Boston guard Avery Bradley said. "Anything can happen as long as we continue to stay positive and play as hard as we can."
The Warriors, one win from back-to-back NBA titles last June before Cleveland made the greatest comeback in finals history to deny them a repeat, wait until Tuesday to open round two at home against Sunday's winner between Utah and the Los Angeles Clippers.
Golden State has been nagged by injuries, including a calf injury to star forward Kevin Durant, and health issues with coach Steve Kerr, who has missed two games and is uncertain for the remainder of the playoffs.
The other Western Conference semi-final showdown matches Texas rivals San Antonio and Houston, their first playoff meeting since 1995 after a season where their four meetings all went down to the final minute.
- 'King' of the road -
James has won at least once on the road in 27 consecutive playoff series dating to 2009 and in 35 of 38 over his 14-year career.
"I just like the adversity of the road," James said. "I love the 'Tonight is not the night' LeBron slogans. I love the 'You're overrated' and all those things."
He might hear it a lot. Despite 31 home wins, second best in the NBA this season, the Cavaliers won't have the home-court edge again in the playoffs if form holds.
Cleveland and Toronto each went 51-31 this season and while Cleveland went 3-1 against the Raptors to gain the home-court edge, three meetings were last year and the last had many key players sitting out to rest.
The Raptors pushed Cleveland to six games last year and won't likely vanish easily this time.
"I know what we have in that locker room, and that's some fighters and scrappers," Raptors coach Dwane Casey said.
The Celtics, 2-2 against Washington this season, expect to have guard Isaiah Thomas for game one after her attended his sister Chyna's funeral Saturday. She was killed in an auto accident two weeks ago, but Thomas has not missed a game.
"I don't know (how he played)," Bradley said. "It's truly amazing."
Celtics coach Brad Stevens is more concerned about the man than the games.
"If he decides when he gets there that it's too much, that's OK. That's fine," Stevens said. "This (grieving) is a lot more important."
Thomas averaged 27.8 points a game against the Wizards this season while Washington guards John Wall and Bradley Beal together averaged almost 40 points against Boston.
Washington led the NBA with 20.7 fast break points and 9.2 steals a game in round one.
"It's playoff time," Beal said. "It's winning time and we're going to do whatever it takes."
- Kerr status still uncertain -
While Durant has rested his calf, Kerr missed practice again Saturday as he battles nausea, headaches and neck pain related to back surgery two years ago.
Warriors assistant coach Mike Brown guided Golden State in his absence and could be pressed into duty throughout the playoffs. He's a former Cleveland coach who 10 years ago guided James and the Cavs into their first NBA Finals, where they lost to San Antonio.
The Spurs are powered by Kawhi Leonard while James Harden sparks Houston. Harden averaged 29.8 points, 12.5 assists and 9.0 rebounds against the Spurs, who boast the NBA's top defense and two-time NBA Defensive Player of the Year Leonard.
San Antonio was 3-1 against the Rockets but three games were decided by two points and the other by only six.