Cooper Flagg, the highly anticipated No. 1 overall pick, made his NBA 2K26 Summer League debut for the Dallas Mavericks against the Los Angeles Lakers, showcasing a mixed performance that left observers with a consensus feeling of his immense potential. Despite a challenging shooting night where he missed 16 of 21 shots, including all five from beyond the arc, Flagg demonstrated a comprehensive game that hinted at his future impact on the league. Former Mavericks owner Mark Cuban noted Flagg's mature approach, stating, "He didn’t try to do too much and say hey, I’m the No. 1 pick and I’m going to show you why. He played basketball." Cuban also emphasized Flagg's young age, highlighting that he is "only 18."

Beyond his struggles with shooting efficiency, Flagg's debut was marked by strong rebounding, an impressive sense of direction and flow on the court, confident command of the floor, and effective defense. His advanced basketball intelligence and maturity, despite his youth, were evident throughout the game. In a crucial late-game sequence, Flagg delivered a decisive block and then, in transition, provided the assist for the go-ahead basket, securing an 87-85 victory for the Mavericks. This performance, reminiscent of other top rookies who faced initial shooting difficulties in Summer League, such as Victor Wembanyama's 2-for-13 debut two years prior, underscores the nature of these early development games.

One of the most immediate highlights of Flagg's debut was his first bucket in a Mavericks uniform: a "big-time slam" after an all-out sprint, which instantly energized NBA social media and the Mavericks fanbase. Fans, including Kansas City Chiefs quarterback Patrick Mahomes, reacted enthusiastically to the poster dunk. Flagg's strong attack on the rim and ability to draw contact for an "and one" opportunity further showcased glimpses of his stardom, despite finishing the first quarter with six points on 3-9 shooting.

The Mavericks' acquisition of Flagg as the No. 1 overall pick was a significant stroke of fortune, given their low 1.8% chance of winning the Draft Lottery. This pick represented a "franchise-saving moment" for a team that had recently endured a public relations debacle, trading Luka Dončić, seeing Anthony Davis suffer an injury, Kyrie Irving tear his Achilles, and ultimately failing to make the playoffs just a year after reaching the NBA Finals. With Flagg's arrival, Mark Cuban expressed renewed hope: "Whatever challenges we had, we now have hope. That changes everything. We just got to hold on until Kyrie gets back."

Mavericks coach Jason Kidd has ambitious plans for Flagg, intending to utilize him at times at point guard next season, particularly until Kyrie Irving returns from Achilles rehab. Kidd expressed confidence in Flagg's ability to "run the show" despite his inexperience in that role, also noting his comfort at playing the two and three positions. This strategic positioning highlights Flagg's versatility at 6-foot-9 with a sure dribble.

Flagg's debut also featured an intriguing matchup against Bronny James, who was making a return trip to Summer League. While Flagg posted up the 6-foot-2 James, resulting in a loose ball and a foul call, James himself struggled offensively, missing six of eight shots, including a potential game-winning three-pointer. Post-game, Flagg candidly assessed his own performance, stating, "That might be one of the worst games of my life… but I’m going to be alright. Just glad we got the win. So that’s what really matters to me." He acknowledged the tough adjustment from Duke to the NBA but embraced his new teammates' support.

The Mavericks coaching staff echoed the positive sentiment. Assistant coach Josh Broghamer noted Flagg's ability to "make the right play, over and over again" despite being trapped full court. Jason Kidd praised Flagg's professionalism, crediting his family for his maturity. Kidd highlighted Flagg's love for basketball, his background of playing "outside" even in Maine's cold weather, showcasing his toughness. Flagg's unique situation as a No. 1 pick joining a non-rebuilding team, rather than a struggling one, positions him similarly to Tim Duncan joining the Spurs with David Robinson in 1997. Cuban emphasized this, stating, "You’ve got multiple Hall of Famers," referring to Klay Thompson, Kyrie Irving, and Anthony Davis on the team, which "takes all the pressure off." This allows Flagg to work on his game without being the primary focus. With plenty of time ahead, his initial shooting numbers are unlikely to define his rookie season or Summer League performance.