Only one first-round NBA playoff series (Celtics-Pacers) is over, but six more teams are on the brink of elimination.

Which players and teams have been the biggest surprises and disappointments so far? And what does this mean for the rest of the postseason and the future of these franchises?

Our NBA experts break down the notable teams in each conference, including the Boston Celtics, Oklahoma City Thunder, Portland Trail Blazers and Philadelphia 76ers. Plus, they make predictions for what will happen the rest of the way.

1. What has been the biggest surprise so far in the East?

Kirk Goldsberry: Boston's sweep. Just when I was about to give up on the soap-opera Celtics, they had the exact series they needed versus Indiana, and they suddenly look like a dangerous opponent for anyone. Of course, the Pacers were short-handed, but Boston did everything it needed to do to gain confidence going into a second-round series against the vaunted Milwaukee Bucks. If the Celtics coalesce, look out. Editor's Picks How Klay Thompson got his team ready for Game 4

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Kevin Pelton: I don't think any of the teams have been particularly surprising, so I'll go with something I mentioned on Monday's Hoop Collective podcast: the ability of Boban Marjanovic to stay on the court for extended minutes. Marjanovic already has logged more playing time than he did in the 2016 playoffs for the Spurs, when his pick-and-roll defense was an issue. Boban's role has been crucial for the 76ers given Joel Embiid missing a game and the team needing to limit Embiid's minutes when he is active.

Tim Bontemps: Jared Dudley's leap into the national consciousness. Dudley has had a long, fine career in the NBA, taking Shane Battier's place as one of the league's premier advanced-stat-darling role players. But in this series against the 76ers, Dudley has become a huge factor, both because of his ongoing feud with Ben Simmons (though that began with his initial comments about Simmons being taken a fair bit out of context) and for his role in the Game 4 fracas after Embiid's second hard foul of the first round on Jarrett Allen. The playoffs always create surprising storylines and personal battles, and Dudley's emergence in this way in Brooklyn is no different.

André Snellings: The way that the Magic and Nets both came out and punched their more powerful opponents in the mouth on the road in their opening games. The East is very stratified, especially since Victor Oladipo's untimely injury, with four teams that are head and shoulders above the others. It wouldn't have surprised me if all four series were sweeps, so it was startling to see the Magic and Nets come in and win. It appears that the more powerful teams have since taken control, but those we're-coming/we-ain't-scared first impressions bode well for the future in Brooklyn and Orlando.

Bobby Marks: The play of Tobias Harris. After the Game 1 loss to Brooklyn, in which Harris had four points, people were ready to label him a regular-season player. Now heading into Game 5, the forward has become the 76ers' most consistent option. Not only has Harris averaged 24 points and nine rebounds and shot 50 percent from the field in the three straight wins, but the 76ers are plus-19.3 when he's on the floor. Without the play of Harris, Philadelphia would be looking at a 3-1 deficit, on the verge of being eliminated in the first round.

2. What has been the biggest surprise so far in the West?

Pelton: How Portland has controlled the series against Oklahoma City. The Blazers have had answers for everything that ailed them in last season's sweep by the New Orleans Pelicans. When the Thunder have forced the ball out of the hands of Damian Lillard and CJ McCollum, fellow starters Al-Farouq Aminu, Enes Kanter and Maurice Harkless have made big plays. And Lillard and McCollum have been forces without forcing the issue.

Snellings: I am probably higher on the Rockets than just about anyone, and it's still shocking how easily they've handled the Jazz so far. The Jazz were considered almost dark-horse contenders after finishing the season 30-11 in the second half, but the Rockets are dismantling them. The Jazz lost the first two games in the series by a combined 52 points, then returned home and couldn't win even with James Harden having a historically awful shooting night. The gap between the No. 4 and 5 seeds in the West wasn't supposed to be this large.

Marks: The resiliency of the young players in Denver. It is rare that we are writing about a No. 2 seed as a surprise with the series tied 2-2, but the Nuggets have played their best basketball when backed into a corner. We saw it in Game 2 when Jamal Murray scored 21 points in the fourth quarter as the Nuggets came back in a must-win game. After dropping Game 3 on the road, facing the possibility of returning home in a 3-1 hole, Denver played its most complete game of the season. Out of Denver's 117 points scored, 97 were from players who had never won a road playoff game.

Goldsberry: The Blazers. Coming out of last year's epic playoff debacle, Portland looks like a completely different animal this postseason. Lillard has been brilliant. McCollum has been strong. But they've managed to survive the Jusuf Nurkic injury in part because Kanter has been solid, even on defense. I did not see that coming.

Bontemps: I thought Oklahoma City would beat Portland, mostly because I thought Portland was sunk after the devastating season-ending injury to Nurkic. Instead, the Blazers look like they're going to make it to the Western Conference semis, and I would pick them as the favorites on their side of the bracket to make the West finals. Lillard has completely outplayed Russell Westbrook, and the always-underrated Terry Stotts has done an excellent job of coaxing better play out of Portland's supporting cast. After years of playoff failures in the Pacific Northwest, a combination of Portland's play and the bracket breaking in the right direction could lead to the kind of breakthrough for which Lillard and the Blazers have been dying.

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3. What has been the biggest disappointment so far in the East?

Marks: Indiana. The disappointment is not with the Pacers getting swept by the Celtics but what might have been had Victor Oladipo not suffered a season-ending right knee injury in late January. At the time, the Pacers were rolling. Though Indiana stayed afloat, winning 48 games, the playoffs showed the challenge of manufacturing offense without Oladipo on the court. The Pacers averaged 95.8 points per 100 possessions, down from 109.3 in the regular season. 2019 NBA Finals Find everything you need to know about Toronto's first NBA title. • Raptors in 6: News, reaction and more

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Snellings: The status of Joel Embiid's knee. Though he has played in three of four games thus far, the fact that he has missed time and been listed as questionable or doubtful is very concerning for a team that otherwise could have legitimate championship aspirations. The top of the East shapes up as a slugfest, and Embiid should be right in the middle of it. If his knee issues persist, it could rob us of what should be some classic basketball over the next few weeks.

Bontemps: As a neutral party, I view the biggest disappointment as the Nets failing to win Game 4 and make sure this series with the Sixers -- easily the most entertaining one of the first round, regardless of conference -- goes at least six games. Nets-Sixers has had it all -- drama on and off the court, big individual performances, contrasts in styles, strategic adjustments; you name it, this series has had it. Now, though, it is likely to end Tuesday in Philadelphia, where the Sixers can close things out on their home court in Game 5.

Goldsberry: The Pistons. They showed some intriguing signs of competence late in the season, but they simply didn't look like they belonged in the playoffs. Yes, Blake Griffin missed the first two games with injury, but even with him available, they couldn't put anything together. This once-proud franchise now has lost an NBA-record 14 playoff games in a row. If that's not a disappointment, I don't know what is.

Pelton: Nikola Vucevic, so good during a regular season that resulted in both his first All-Star nod and his first playoff appearance in Orlando, has been unable to reach the same level during the playoffs. He's averaging just 12.5 points on 37.5 percent shooting and was largely a nonfactor in the Magic's Game 1 win. Granted, playing against Marc Gasol and Serge Ibaka is a challenge, but Orlando has needed more from Vucevic.

4. What has been the biggest disappointment so far in the West?

Bontemps: I'll give this as a tie to Utah and Oklahoma City (and specifically Russell Westbrook). Utah losing to Houston is one thing; Utah getting annihilated in the first two games of this series is another. The Jazz were much better in Game 3, but they still couldn't find a way to win a game at home in which James Harden went 3-of-20 from the floor, and now they could get swept out of the playoffs. Westbrook, meanwhile, is shooting 36 percent from the floor, and the Thunder look like they're about to lose in the first round for a third straight season. When the bracket broke the way it did, with Golden State and Houston on the opposite side, that's not what the Thunder were expecting to happen.

Marks: Russell Westbrook. Though there is plenty of blame to go around (including the lack of shooting on the roster), all eyes are on Westbrook. After shooting 5-of-20 in a Game 2 loss on the road, Westbrook scored one point in the second half at home in Game 4. That loss has Oklahoma City down 3-1 and on the verge of losing in the first round yet again.

Pelton: The Utah Jazz failing to win a game thus far against the Houston Rockets. I expected this to be the closest first-round series, but the Rockets dominated at home and pulled out a win in Salt Lake City despite James Harden missing his first 15 shots, putting them a game away from a sweep. Utah could join the 2004 Memphis Grizzlies and 2008 Denver Nuggets as just the third team since the first round went to best-of-seven to win at least 50 games during the regular season and none in the playoffs.

Snellings: The two best teams in the conference won't face each other in the conference finals. Last season's Western Conference finals -- between the defending champion Warriors and the top-seeded Rockets -- was the de facto NBA championship due to the inequity between the East and West. This season, that matchup appears destined to occur in the second round, too early and with the stage not fully set to appreciate the magnitude. Of course, the cynic might point out that having the Rockets and Warriors play in the second round could be a benefit due to the history of health issues on both sides, so perhaps playing earlier can prevent any more major injuries from marring the outcome.

Goldsberry: Utah, Utah, Utah. The Jazz played terrific basketball after the All-Star break but have looked terrible in the first round. Not only has their great defense failed to show up, but they have the worst offensive rating of any West playoff team. One big problem: 3-point shooting. They've made only 25.5 percent of their 3s against Houston, and Jae Crowder, Thabo Sefolosha and Joe Ingles have each been worse than that. Yuck!

5. What is your bold prediction for the rest of the postseason?

Snellings: The dominant Warriors, winners of three of the past four NBA championships, will not win the title this season. There is a very good chance that they don't even make the conference finals, as the Rockets appear poised to take them down. The team that represents the East also has a very legitimate shot to take down the representative from the West. Said another way: If given the choice between the Warriors and the field, this season I'm taking the field.

Goldsberry: The Larry O'Brien Trophy is moving East. Like Andre, I think the Warriors are vulnerable, but I also think whoever comes out of the East will take home the title.

Pelton: Nikola Jokic, currently 0.7 assists per game away, averages a triple-double.

Bontemps: That Golden State beats Houston in five games in the Western Conference semifinals. For all of the growing belief that the Rockets can beat the Warriors in a series, I think that the Warriors -- if healthy -- will end that series more quickly than many would expect. And here's a bonus one: Toronto will win the East.

Marks: A Joel Embiid flagrant foul will cost Philadelphia a chance at reaching the conference finals. After picking up flagrant fouls in Games 2 and 4, Embiid is two points shy of serving a one-game suspension.