The Mavericks’ season came to an end with a whimper Monday night as Boston blew out Dallas, 106-88, in Game 5 of the NBA Finals.The Celtics clinched the franchise’s NBA-leading 18th championship, breaking a tie with the Los Angeles Lakers behind 29 points, 11 assists and seven rebounds from Jayson Tatum.Boston led wire-to-wire and by double digits most of the night. The closest Dallas got to Boston was in the second quarter whenDerrick Jones. Jr. cut Boston’s lead to 48-39, but the Celtics responded with a 12-3 run to stretch the lead to 18 after back-to-back 3s from Finals MVP Jaylen Brown and Derrick White.To make matters worse, with just 4.7 seconds remaining before halftime Doncic missed the free throw of a possible three-point play and Celtics guard Payton Pritchard launched a 50-foot heave that he knocked down just before the buzzer to put Dallas in a 67-46 halftime hole.The game was never in doubt after this point as Boston led by double digits the entirety of the second half en route to its first NBA crown since 2008..Tatum outduels DoncicDoncic has been the best player on the floor in just about every game this series with the exception of Monday’s. While Doncic was held to single digits, Tatum produced 16 points, nine assists and five rebounds in the first half.Tatum’s playmaking was extremely valuable, but the All-NBA forward also was much better at attacking the rim instead of settling for long 3-pointers. Tatum had at least four baskets at the rim which led to his most efficient half of the series. Doncic got into more of a groove in the third quarter with nine points, but the Mavericks never got closer than 17 in the period.Tatum helped deliver the dagger in the fourth quarter as he found White for a 3-pointer and then converted a 3-point play on the Celtics’ next possession. After a Kyrie Irving 3-pointer, Tatum answered again with a turn around jumper in the lane to make it 96-75. Tatum chose the best time to have his best game and while Doncic’s numbers were OK on paper, much of it came while the game was already in hand.Doncic finished with 26 points, 12 rebounds and four assists.Irving struggles in Boston again Irving has said he’s made peace with his time with Boston that ended on bad terms as he left in free agency. However, ever since ...