OKLAHOMA CITY — The NBA entered Sunday’s regular-season finale with a heightened level of intrigue with 15 out of 20 seeds still undetermined for the rapidly approaching postseason.That mystery factor didn’t apply for the Mavericks, who’d already clinched the fifth seed, so their one-sided 135-86 loss to the Oklahoma City Thunder was a game with little significance outside of the development of their young players.For the Thunder, the stakes were notably higher. The No. 1 seed and home-court advantage in a stacked Western Conference hung in the balance. Oklahoma City entered the game in a three-way tie for first place with Denver and Minnesota.The Thunder achieved its goal of securing the No. 1 seed with the win over the Mavericks, combined with Minnesota’s loss to Phoenix. The Nuggets beat the Grizzlies, which creates a two-way tie with Oklahoma City. Since the Thunder owns the tiebreaker, it’ll receive sole possession of the top seed in the west.The 49-point loss marked the second-largest margin of defeat in franchise history, just nine points shy of the all-time record of 58 – set during the 1992-93 season when Dallas suffered a 139-81 loss to the Sacramento Kings.During his pregame media availability, Mavericks coach Jason Kidd said the main goal of Sunday’s game was to come out of it healthy. That mission was accomplished, but not without suffering the largest margin of defeat this season. The 49-point loss surpassed the previous season-high of 38 points in a loss to the Utah Jazz on New Year’s Day.“No one got hurt, which was positive,” Kidd said after the loss. “Oklahoma is the number one seed. They had a heck of a year. We didn’t shoot the ball straight, but there’s a lot of positives in this. The biggest thing is we’re coming out healthy and now we can close the door on our regular season and now we can get started on the playoffs.”The decision to rest eight rotation players was the largest factor for the blowout loss. The Mavericks were without Luka Doncic (left ankle soreness), Kyrie Irving (left hamstring soreness), Daniel Gafford (right elbow soreness), P.J. Washington (right ankle sprain), Dereck Lively II (right knee sprain), Derrick Jones Jr. (left shoulder sprain), Dante Exum (right foot sprain) and Maxi Kleber (low back spasms) – a group that is likely Kidd’s eight-player playoff rotation.As a result, Kidd used a first unit of Jaden Hardy, Tim Hardaway ...