DALLAS -- Coughing and wheezing, his temperature spiking to 101, worn out from hardly sleeping the night before, Dirk Nowitzki went through three miserable quarters in Game 4 of the NBA finals.

Yet the fourth quarter was his time to shine. Again.

And now the Dallas Mavericks and Miami Heat are starting over in the NBA finals, this best-of-seven series reduced to a best-of-three.

Nowitzki fought through a sinus infection and everything else that ailed him and his team to power a 21-9 run over the final 10:12, lifting the Mavericks to a memorable 86-83 victory Tuesday night.

In the final period, Nowitzki scored 10 of his 21 points -- including a driving right-handed layup that spun in off the backboard with 14.4 seconds left -- and grabbed five of his 11 rebounds as Dallas pulled off its second stunning finish this series.

"Just battle it out," Nowitzki said, sniffing throughout his postgame interview with his warm-up jacket zipped all the way up, still in his uniform instead of changing into street clothes like the NBA prefers. "This is the finals. You have to go out there and compete and try your best for your team. So that's what I did."

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 night in Dallas, and Nowitzki vowed to be ready.

"There's no long term," Nowitzki said. "I'll be alright on Thursday. ... Hopefully I'll get some sleep tonight, take some meds and be ready to go on Thursday."

Nowitzki wasn't as dominant as Michael Jordan when he scored 38 points despite a 103-degree fever in Game 5 of the 1997 finals -- but it was that kind of performance down the stretch. With everyone knowing he wasn't at full strength, the Mavs still ran their offense through him in the fourth quarter, and he delivered, making 2 of 6 shots and all six of his free throws.

If the Mavericks wind up winning their first championship, what Nowitzki's done this series will go down among the greatest. Remember, in Game 2 he bounced back from a torn tendon in the tip of his left middle finger to score the final nine points in Dallas' 22-5 rally, including two left-handed layups among his final three baskets.

"The average person, you know, has sick days and battling 100-something (fever), it's just tough to get out of bed," Dallas center Tyson Chandler said. "This guy is playing against the best athletes in the world."