Cooper Flagg played in his 14th straight game for the Dallas Mavericks on Sunday against the Portland Trail Blazers. The No. 1 pick has faced nearly all coverages and teams, but the Trail Blazers were a different beast due to their high ball pressure and physicality. Flagg has struggled in some of these matchups for stretches.On Sunday, though, he had a solid start. In the first quarter, Flagg played 7:36 minutes. He scored two points, one rebound and had two assists. His only field goal came off a dunk in transition, which transpired with his activity on defense.Flagg returned in the second quarter with 8:13 left. He took two more shot attempts and missed both. Nevertheless, Flagg remained active in other areas. He added three rebounds and a block to his box score.Flagg was off to a hot start in the third quarter. After taking only three attempts in the first two quarters, the No. 1 pick was more involved in the third with five shots in the first five minutes of the third. Fagg made four of those, taking his point total to 14 and sparking a turnaround for the Mavericks.Flagg had a relatively cold stretch the rest of the way through the regulation. He added three points to his tally in that stretch, including one from the free throw line. Flagg had two huge moments in the clutch as he blocked an and-1 shot to keep the Mavericks in the contest, but he squandered the opportunity for a game-winner on the other end.Deni Avdija missed for the Trail Blazers, forcing another overtime game for Flagg and the Mavericks.Cooper Flagg had a phenomenal overtime as he scored four points, two rebounds and one assist. It was a one-possession game with two minutes left when Flagg made key back-to-back plays that proved pivotal.The first was a turnaround hook shot, giving Dallas a 128-126 lead, followed by a rebound and full-court pass to P.J. Washington, which extended the Mavericks' lead to 132-129.The Mavericks won 138-133.Here's Cooper Flagg's final stat line against the Trail Blazers:PTSFG3-PT FGREBASTTOSTLBLKPF+/-FTM219-161-3850123102-3Cooper Flagg feels it's coming together for him and the Mavericks The Mavericks snapped a three-game losing streak and improved to 4-10 on the season behind Cooper Flagg's 19-point second half. The Mavericks had been in clutch situations more than anyone before this clash, with 10 of their 13 games going down to the wire. Sunday was the 11th time they found themselves in a similar position.After so many reps, the Mavericks finally executed their game when each possession mattered. Flagg reflected on this journey after beating the Trail Blazers, saying:"It's those experiences for sure. ... It's just coming together, gelling, figuring out our chemistry, figuring out our organization, and where we want to be on the court, and it's coming together."It has been a learning curve for Flagg, too. He's had ups and downs in the clutch, but on Sunday, he was more composed and made decisive plays that helped the Mavericks win.