WASHINGTON (Reuters) - The Washington Wizards capped a stunning comeback in the final minute to upset the Eastern Conference-leading Boston Celtics 85-83 on Saturday.

John Wall's three-point basket off the backboard as the shot clock ran out gave the Wizards an 84-81 lead with just 58 seconds left, and they held on as time expired to snap Boston's five-game winning streak.

"I didn't call it," Wall said of his key shot. "I knew it was going to hit backboard, but I thought it was going to be a hard brick. It could have broke the backboard, but luckily it went in for us, and it was a momentum changer."

"I thought we came out, played hard, got a big lead, and then I thought we went showtime," said Celtics coach Doc Rivers. "I thought we decided to just kind of play, not compete. So I really thought we deserved to lose the game."

Washington's comeback was keyed by improved defense in the second half. The Wizards held the Celtics to just 27 points after being outscored 56-46 in the first half.

Rashard Lewis led the Wizards with 18 points while JaVale McGee and Wall each scored 16. Kevin Garnett paced the Celtics with 17 points.

(Reporting by Mike Mouat in Windsor, Ontario; Editing by John O'Brien)