Top seeds Miami and Phoenix moved to within one win of the NBA conference finals on Tuesday after scoring blowout victories against Philadelphia and Dallas.

In Miami, Jimmy Butler scored 23 points in a balanced offensive effort as the Heat thrashed the Philadelphia 76ers 120-85 to seize control of their best-of-seven Eastern Conference playoff series.

It was a similar story in Phoenix, where the Suns overwhelmed the Mavericks to score a 110-80 win in the Western Conference playoffs.

Both Miami and Phoenix now lead their respective series 3-2, needing just one win from their final two games to advance to the conference finals.

Dallas had roared back into contention to level the series at 2-2 on Sunday after dropping games one and two in Phoenix last week.

But normal service resumed as Phoenix reasserted themselves emphatically in front of their home fans on Tuesday.

Devin Booker led the Phoenix scoring with 28 points while Deandre Ayton had 20 points with nine rebounds.

Dallas had led by as much as eight points during an even first half that saw the Suns lead by three at the break.

But Phoenix erupted in the third quarter, outscoring Dallas by 33-14 to take a stranglehold on the contest.

Luka Doncic led the Mavericks scorers with 28 points and 11 rebounds with Jalen Brunson providing support with 21 points.

- Sixers outplayed -

In the Eastern Conference, Miami look poised to punch their ticket to the next round after dominating a subdued Philadelphia.

Few would bet against Miami closing out the series in game six on Thursday against a Philadelphia team who were outplayed in every department.

Butler was one of seven Miami players who finished in double figures, with Max Strus contributing 19 points and 10 rebounds and Gabe Vincent adding 15 points. Victor Oladipo added 13 off the bench while Bam Adebayo had 12.

Philadelphia meanwhile struggled to get going at any stage, with Joel Embiid, wearing a protective facemask once more to shield a fractured orbital bone, clearly not firing on all cylinders.

Embiid finished with 17 points to lead the Sixers scoring, while James Harden had just 14. Overall Philadelphia shot just 31 of 85 from the field.

"We did what we were supposed to do once again, we won at home," Butler said.

"We're a different team when we make shots. But I don't like that, I want us to get stops no matter what and then worry about making shots."

Asked what it will take to clinch the series in game six on Thursday, Butler replied: "Us to continue to play basketball the right way, us to get stops and not rely on making shots.

"I promise you if we don't give a damn about making shots and just concentrate on defense, we will win."

Sixers coach Doc Rivers was at a loss to explain his team's failure to show up.

"They were just so much more engaged, more physical," Rivers said of Miami.

"There's a lot of disappointment from all of us tonight.

"We played at a snail’s pace, had just 85 shots, turned the ball over. Everything they did tonight was harder and better than us.

"Their energy was better, their toughness was better."

Asked what aspects of the game had gone wrong, Rivers replied: "I'll have to watch the tape -- or burn the tape. Probably watch it because I have to, and then I'll burn it.

"But we'll be ready next game because we have to be."