The National Basketball Association conference semi-finals kick off later on Monday following one of the wildest and most exciting starts to the playoffs in years.

Five of the eight surviving teams were pushed to seven games in the first round, with the Brooklyn Nets needing a last-second block to beat the Toronto Raptors.

Their reward for winning is an Eastern Conference clash with the two-time defending champion Miami Heat, who have had a week off after sweeping the Charlotte Bobcats in four games.

Led by LeBron James, Miami rebounded from a shaky end to the regular season to lift their game when it mattered.

They will open the series at home on Tuesday as overwhelming favorites to beat Brooklyn even though the Nets swept Miami in their four meetings during the regular season.

"Teams are more prepared," James told reporters when asked about his team's prospects of beating the Nets in the playoffs.

"You have more time to prepare for a team and prepare for individuals. What you did in the regular season doesn't matter in the postseason."

The winner of that series will face either the Indiana Pacers or Washington Wizards, who open their series on Monday, for the Eastern Conference title.

The top-seeded Pacers struggled in the first round against the eighth-ranked Atlanta Hawks, needing to win the last two games to advance after trailing 3-2 in the best-of-seven series.

Indiana shooting guard Paul George said his team's tough first-round series was not what the team had really wanted but they made it through and it all starts against the Wizards.

"It's a process. Sweeping a team is a luxury, it's ideal but it's not going to happen sometimes," he said.

"Many teams have been drawn out to a Game 7 to start their playoff run off. It's one game at a time. That's what it comes down to."

The Wizards pulled off the biggest upset of the first round when they crushed the Chicago Bulls 4-1 and Washington shooting guard Bradley Beal said his team needs to be at their best against the Pacers.

"We'll be ready from the jump. Hopefully they'll be pretty tired," Beal said. "We've got to get off to a pretty good start against them because we know what they're capable of doing."

Last season's Western Conference champions, the San Antonio Spurs, face the Portland Trail Blazers starting on Tuesday.

The Spurs needed seven games to see off the Dallas Mavericks while the Trail Blazers upset the Houston Rockets in six after Damian Lillard's three-point buzzer beater clinched the series.

The veteran Spurs, with all their big-game experience, are favorites to beat the Trail Blazers, who are reveling in their role as underdogs after reaching the second round for the first time since 2000.

"Anytime you win, you're going to get confidence," Portland small forward Wes Matthews said. "To win in the fashion that we did, where the games were always tight and nothing was safe, we learned a lot.

"I think that was a learning process for everybody about how valuable all these possessions were and how fragile it could be and a wrong bounce could send you to a Game 7 that you don't want to be in. Now, I don't think there's a limit."

Oklahoma City Thunder will face the Los Angeles Clippers in the other Western Conference semi after both teams won their first-round series in seven games.

Oklahoma City beat the Memphis Grizzlies while the Clippers saw off the Golden State Warriors to end a week when the focus had all been on their embattled team owner Donald Sterling.