The Dallas Mavericks are learning, in real time, how unforgiving the margin can be when continuity is missing and defense slips.
SAN ANTONIO — The Dallas Mavericks’ post-deadline transition took another hit Saturday night, as the team fell 138–125 to the San Antonio Spurs at Frost Bank Center, extending a losing streak that has followed the team through a week of roster upheaval and on-court adjustment.
The loss was Dallas’ seventh straight and its second in three nights against San Antonio, a matchup that highlighted the contrast between a Spurs group firmly established near the top of the Western Conference and a Mavericks team still piecing itself together. San Antonio scored a season-high 81 points in the first half and controlled the game’s tempo almost from the opening tip, forcing Dallas to chase from behind for most of the night.
The Mavericks briefly showed signs of rhythm in the second quarter, pushing ahead 51–49 midway through the period. That stretch, fueled by ball movement and perimeter shot-making, proved short-lived. San Antonio responded by accelerating the pace, turning missed shots into transition opportunities and steadily widening the gap before halftime.
By the break, the Spurs had built an 81–67 advantage, the most points Dallas has allowed in any half this season. The margin only grew from there as San Antonio opened the third quarter with a run that effectively decided the game.
San Antonio guard Stephon Castle authored the defining performance of the night, recording 40 points, 12 rebounds and 12 assists for his second career triple-double. His stat line placed him alongside David Robinson as the only players in franchise history with a 40-point triple-double, and his impact was felt across every phase of the game as Dallas struggled to contain him in space.
While the Mavericks focused more defensive attention on Victor Wembanyama than they had earlier in the week, the shift left Castle free to dictate terms. San Antonio’s lead swelled to as many as 28 points late in the third quarter, and the outcome was largely settled before the final period began.
One of the few encouraging signs for Dallas came from Marvin Bagley III, who made his Mavericks debut after arriving in the Anthony Davis trade. Bagley finished with 16 points, 12 rebounds and four blocks in 24 minutes, providing energy and physicality off the bench.
His work on the offensive glass reached the record books. Bagley collected eight offensive rebounds, setting the franchise mark for the most in a Dallas debut, surpassing the previous record of six set by Chris Gatling in 1996.
Dallas also received 19 points from Klay Thompson, 18 from Brandon Williams and 17 from Max Christie, but the scoring balance did little to offset persistent defensive breakdowns and a transition game that never stabilized.
Rookie Cooper Flagg, who entered the night riding a four-game streak of 30-point performances, was limited to 14 points in 26 minutes after dealing with back stiffness. He did not return in the fourth quarter as the Spurs pulled away.
After the game, Mavericks coach Jason Kidd addressed both the defensive issues and the challenge of integrating new players on the fly.
“I thought the new pieces were fine,” Kidd said. “Our transition defense wasn’t very good. The shots we got in the first game, we made them, and tonight we didn’t. They ran on us.”
Kidd later expanded on Flagg’s night and the decision to hold him out late.
“His back got sore and stiffened up on him, so we couldn’t bring him back,” Kidd said. “I thought he made some great plays that we just didn’t knock down.”
Bagley, reflecting on his first game in a Dallas uniform, emphasized effort as his primary focus.
“I just tried to go out there and play my game,” Bagley said. “No matter what, you’ve got to bring that energy and try to impact the game.”
The Mavericks entered the game shorthanded, with Kyrie Irving and Dereck Lively II still sidelined following surgeries. Khris Middleton did not make his debut after arriving too late to complete his physical, though he traveled with the team and is optimistic he will be available Tuesday in Phoenix.
The broader challenge for Dallas extends beyond one night or one opponent. With multiple new players, injuries to key pieces and a schedule heavy on road games ahead, the Mavericks are navigating a stretch where development, evaluation and results are colliding.
San Antonio, meanwhile, left little doubt about its identity. The Spurs ran decisively, defended with urgency and capitalized on every lapse, reinforcing their status as a team built to punish mistakes.
For the Mavericks, the task now is to absorb the lessons quickly. With the roster still settling and the margin for error shrinking, Dallas’ path forward depends on whether defensive cohesion can catch up to opportunity before the season slips further away.