In a game of dueling masterpieces from Nikola Jokic and Kyrie Irving, neither of them delivered the decisive blow. Michael Porter Jr. attacked a close-out and buried 14-foot floater with 6.5 seconds left, and the Nuggets held on for a thrilling 122-120 win over the Mavericks to complete a perfect five-game homestand on Sunday. “What a weapon to have late in the game,” coach Michael Malone said.