(CNN) -- The NBA Finals are now all-square at 2-2 after the Dallas Mavericks defeated the Miami Heat 86-83 in a thrilling Game Four of the best-of-seven-series.

Once again in-form Dirk Nowitzki top scored for the Mavericks, scoring 21 points, with 10 of these coming in the final quarter, as the lead changed hands no fewer than 12 times on Tuesday.

German Nowitzki, who performed to his best despite suffering from a fever, also helped himself to 11 rebounds, while Shawn Marion scored 16 points and Tyson Chandler finished with 13 points and 16 rebounds for the Mavericks.

Wade turns up Heat on Mavericks

Jason Terry and DeShawn Stevenson made significant contributions from the bench, coming on to score 17 and 11 points respectively for the Mavericks in front of a crowd of 20,430 at the American Airlines Center.

However, the game's overall top scorer was Dwyane Wade with 32 points for the Heat, while Chris Bosh helped himself to 24 points.

But LeBron James struggled to find his shooting form, finishing with just eight points in a disappointing display.

Game five is in Dallas on Thursday before the series switches back to Miami for game six on Sunday.

This year's final is a rematch of the 2006 NBA championship series that Miami took in six games for its first title in franchise history. Dallas has never won the NBA title in its 31-year history.

COMMENT: Because the dallas won against miami now the score is 2-2 so dallas has to continue with that determination if they want to win game 5 if they do their chances of wining the NBA finals will be like 50%, because miami has the same posibility to win.