DALLAS (AP) — Dirk Nowitzki and the Dallas Mavericks have pulled off another stunning comeback, tying the NBA finals at two games each.

And this time, Nowitzki did it while battling the flu.

Nowitzki shook off three poor quarters to score 10 of his 21 points in the final period as the Mavericks outscored the Miami Heat 21-9 over the final 10:12 for an 86-83 victory in a memorable Game 4 on Tuesday night.

The Mavs avoided going down 3-1, a deficit no team has ever overcome in the finals, and guaranteed the series will return to Miami for a Game 6 on Sunday night. Game 5 is Thursday in Dallas.

"We just played with incredible heart and passion," Dallas center Tyson Chandler said.

Dwyane Wade scored 32 points, but fumbled an inbounds pass with 6.7 seconds left. He knocked the ball back to Mike Miller for a potential tying 3-pointer, but it wasn't even close to hitting the rim.

Chris Bosh scored 24 points for Miami, but the Heat got a stunningly unproductive game from their biggest star, LeBron James. He scored only eight points, making just 3 of 11 shots. He contributed nine rebounds and seven assists, but his lack of scoring sticks out because of the loss.

Nowitzki opened the game looking just fine, making his first three shots. But then he missed 10 of 11, and missed a free throw for the first time since Game 4 of the conference finals. By then, word spread of his illness.

With the game — and likely the series — on the line, Nowitzki found a way to come through. He made only 2 of 6 shots, but that included a terrific layup with 14.4 seconds left; he made all six of his free throws.

Hey, if he could win Game 2 with a left-handed layup two days after tearing a tendon in the tip of his middle finger, what's a little temperature?

"We all seen him go through walkthroughs," Chandler said. "Every time he started to talk he started coughing. He was wheezing."

Miami was poised to take a commanding lead in the series when Udonis Haslem hit a jumper that made it 74-65 early in the fourth quarter. It was the Heat's biggest lead and the way Nowitzki was playing, the Mavericks didn't seem capable of pulling off another rally like the 22-5 finish that won Game 2.

Yet Jason Terry — who kick-started that comeback with six straight points — made consecutive baskets, and the surge was on. Terry ended up capping it with two free throws with 6.7 seconds left that forced Miami to need a 3-pointer.

Dallas finally got the balanced scoring attack it wanted.

Terry had 17, Shawn Marion 16 and Chandler had 13 points and 16 rebounds.

DeShawn Stevenson, who moved to the bench so J.J. Barea could join the starting lineup, scored 11 points.

Miami, as usual, got little beyond its three superstars. Miller scored six points, Mario Chalmers had five and Haslem and Joel Anthony each scored four points.

The series is up for grabs now. Both teams are 1-1 at home, so all those stats about who wins under various circumstances seem pretty moot.

The bottom line is, it's a best-of-three series now.

It was an electric night from the start, with 20,430 fans again clad in their blue "The Time Is Now" giveaway T-shirts standing and screaming from the time Kelly Clarkson finished the national anthem.

The score was tight most of the night. Each team had its share of runs, but there also were long stretches of trading baskets.

The Mavs made half their shots in the first quarter, but gave up so many offensive rebounds — nine in the first 10 minutes, matching Miami's total for Game 3 — that the Heat tied it after one period despite shooting only 29 percent.

Miami got going in the second quarter, putting together a 12-2 spurt. Soon after Haslem went to the bench with three fouls, Dallas went back ahead being a 9-0 run fueled by defense: a travel, a charge, a shot-clock violation and two turnovers. Then it was Wade's turn.

He made two tough shots, then somehow got a shot to fall after being hit in the body and arms while driving to the rim. That three-point play started a 7-2 jag that left Miami up 47-45 at halftime.

Both teams sensed the game and series was on the line at the start of the third quarter. The action became more physical and both teams were up for the challenge, putting together six lead changes and five ties in the first 6:11.

In one flurry, Bosh hit a jumper with a man in his face, Barea darted to the rim and somehow got up a shot that then spun off the backboard and rim before falling, followed by Wade making a jumper over Marion as the shot clock was running out. Marion walked away shaking his head, smirking and saying, "I don't know, I don't know." Then Marion came back and banked in a hook shot over James.

NOTES: Stevenson scored in double figures for the first time since Feb. 2. ... Marion's first break this game was longer than he sat out all the previous games. ... Finals jitters? Bosh and Terry each missed their first two free throws. Both were making 81 percent of their foul shots this series. ... Mavs coach Rick Carlisle got a technical foul late in the first quarter for questioning what looked like a questionable call. All Carlisle appeared to say was, "C'mon, Monty," with his hands up and a smirk on his face. ... The elderly fan who appeared shaken up when two players flew into him during the second quarter of Game 3 was back in his usual courtside seat.