Four games into the second round of the NBA playoffs, the No. 1 seeds from each conference find themselves in two different places.

East top seed Boston and West top seed Oklahoma City both made it through the first round with relative ease. After an early stumble to begin Round 2, the Celtics are back home for Wednesday’s Game 5 with a 3-1 series lead over Cleveland, and with a chance to advance to their third consecutive conference final.

Meanwhile, the Thunder return home in a 2-2 tie with Dallas.

Boston is feeling good about how it followed up its Game 2 loss with back-to-back wins in Cleveland. The Celtics didn’t have to contend with Cavaliers’ star Donovan Mitchell, who sat out Monday’s Game 4 with a strained left calf.

But Boston used All-Star Jayson Tatum’s second straight 33-point performance to earn a 109-102 victory in the Celtics’ first game decided by single digits this postseason.

“It felt good. We knew they weren’t just going to go away or back down,” Celtics guard Jrue Holiday said. “So, I think being tested in that way and responding the way we did — we did a pretty good job.”

Cleveland’s mindset is simple, forward Max Strus said.

“Find a way to win. That’s all we can do,” he said.

Dallas missed its chance to go up 3-1, unable to fight off Shai Gilgeous-Alexander’s 34-points as Oklahoma City rallied to a 100-96 win on Monday.

Thunder rookie Chet Holmgren, who finished with 18 points and nine rebounds, put OKC in front for good in the closing minutes. He said it’s no time to relax.

“Anytime you win, it gives you confidence. But we can’t let it be arrogance,” he said. “We have to get back and figure out how to be better. Because the Mavs are going to do the same thing. The job’s not done, obviously. And neither team feels like they’re out of it. We’ve got to get in there and get ready to battle.”

Mavericks guard Kyrie Irving believes they can duplicate their first-round performance when they were tied after four games against the Los Angeles Clippers, and then won back-to-back games to close out that series.

“They’re playing desperation basketball, and we’ve got to play the same,” Irving said. “Just staying even keeled and staying poised. That’s what the playoffs is all about.”

CAVALIERS AT CELTICS

Boston leads 3-1. Game 5, Wednesday, 7 p.m. EDT, TNT

• NEED TO KNOW: The Cavs stayed in Game 4 thanks to 30 points and seven assists from Darius Garland, who picked up the offensive load with Mitchell out. But duplicating those numbers may be tough for Garland, who has just two 30-point games in his playoff career. But Boston is just 3-2 at home this postseason. Its two losses at TD Garden were by a combined 34 points.

• KEEP AN EYE ON: Three-point shooting. One of the reasons Cleveland competed in Game 4 was its advantage from beyond the arc. The Cavs attempted a team playoff-record 48 3-pointers, connecting on 15. Boston went 12 of 32 from 3, below its NBA-leading average of 38 attempts per game this postseason.

• INJURY WATCH: Along with Mitchell, the Cavs also played Game 4 without center Jarrett Allen, out for the seventh consecutive game with the rib injury he sustained last round against Orlando. Boston’s Kristaps Porzingis has also yet to appear in this series as he continues to work back from a strained right calf.

• PRESSURE IS ON: The Cavs are facing elimination for the second time this postseason. Unlike in their Game 7 first-round matchup with Orlando, this time Cleveland will be on the road and possibly without their top star in Mitchell.

MAVERICKS AT THUNDER

Series tied 2-2. Game 5, Wednesday, 9:30 p.m. EDT, TNT

• NEED TO KNOW: The Thunder trailed for most of Game 4 on Monday night but rallied to pull out the win. It was a massive road victory for one of the league’s youngest teams. Oklahoma City allowed fewer than 100 points for the sixth time in eight games. Gilgeous-Alexander scored 34 points in Game 4 and is averaging 29.5 points in the playoffs for the Thunder.

• KEEP AN EYE ON: Dallas’ P.J. Washington. He has picked up some of the scoring slack for Luka Doncic, but the Thunder might be figuring him out. He made 26 of 48 field goals the first three games, but was just 7 of 19 in Game 4. He’s averaging nearly 22 points in the series after averaging just 12.9 in the regular season.

• INJURY WATCH: Doncic. He’s been playing on an injured right knee, and the Thunder, led by Lu Dort, are playing good defense on him. He’s averaging 22 points per game in the series, down from 33.9 in the regular season, and he’s only shooting 39% from the field.

• PRESSURE IS ON: Oklahoma City. The Thunder regained home-court advantage with the Game 4 win in Dallas. The last thing they want to do is give it right back and head to Dallas down 3-2 for Game 6.