Phoenix won't hit the panic button after squandering a two-game advantage in the NBA Finals, but the Suns will need improved ball-handling and rebounding to slow the momentum-fuelled Milwaukee Bucks.

Khris Middleton scored 40 points and Greek forward Giannis Antetokounmpo added 26 points, 14 rebounds, eight assists, three steals and two blocked shots to power the Bucks over Phoenix 109-103 on Wednesday, knotting the best-of-seven series at two wins each.

The Suns, who led by seven in the fourth quarter, committed 17 turnovers, five by star guard Chris Paul to match the Bucks' total, and allowed 17 offensive rebounds.

"We certainly had a lot of self-inflicted stuff," Suns coach Monty Williams said.

Having wasted a 2-0 series edge, the Suns will return to Phoenix for game five on Saturday needing to tighten their defensive work and hustle harder in key situations.

"There's no hitting the panic button. There's no panic. You go back home and look at it and adjust," said Suns forward Cam Johnson.

"It's the finals. You're not going to get away with anything easy. You're not going to coast to any victory."

The Suns are chasing the first title in the team's 53-year history while the Bucks seek their second overall crown and first in half a century.

"It's high stakes, very high stakes," Johnson said. "We know what's on the line."

Milwaukee closed on a 12-4 run in the last 2:07 to win after the Suns had led most of the night, Phoenix wasting a 42-point performance from guard Devin Booker, who missed much of the fourth quarter with foul trouble.

"We was holding it down, defending at a high level," Booker said. "We have to close possessions and that's something that hurt us."

Paul, in the first finals of his 16-year NBA career at age 36, said each team knows the other well and performance will decide the champion.

"You know the sets. They can call out our plays, we can call out their plays. It's about execution," Paul said.

"Down the stretch we've got to box out, we've got to execute. We're a team that's closed out games like that all season long.

"So this is a tough one but we got to bounce back. That's why we fought all season to get home court."

The Suns, who would host a game seven on July 22, lost twice in a row in the playoffs early to the Los Angeles Lakers and responded by winning nine games in a row.

"You can't just bank on the fact that you got home court," Paul said. "You got to go out there and play the game. You got to execute, so we'll do that.

"We tend to respond well. We know what we got to do — be better."

Suns coach Monty Williams isn't worried about how Paul will respond with his best chance at an NBA crown now in jeopardy.

"We expect him to bounce back," said Williams. "He had five [turnovers] but we had 17 and they scored 24 points. That was pretty much the game right there.

"It wasn't just Chris. As a team, we've got to take better care of the ball."