Cooper Flagg was in action during the Dallas Mavericks' fourth and final preseason game against the LA Lakers at the T-Mobile Arena in Las Vegas on Wednesday. Flagg was in the starting lineup alongside Anthony Davis, Dereck Lively II, P.J. Washington and Klay Thompson.Flagg played extended minutes as part of his ramp-up process for the team's opening night game next week. The 6-foot-9 forward delivered a steady performance and impacted the game in a multitude of ways as Dallas ended its preseason campaign with a win.Flagg finished with 13 points, two rebounds and three assists in 28 minutes. He shot 5 of 11 from the field, including 0 of 2 from 3-point range and 3 of 3 from the free-throw line. He didn't commit any turnovers on the night and recorded a -6 rating.Cooper Flagg highlights vs. Lakers (Oct. 15)Flagg received his first welcome to the NBA moment as Gabe Vincent cooked the Mavericks rookie with five 3-pointers early in the first quarter. The former Duke phenom remained unflustered and soon found his groove on offense after a slow start to the game.Just like the previous contest, Flagg started as the team's primary point guard. He recorded one assist in the opening period but scored nine points on 4 of 6 shooting from the floor.Flagg was quiet in the second quarter, attempting just one shot. He entered the halftime break with nine points on 4 of 7 shooting, including 0 of 1 from beyond the arc, along with one assist.Flagg came out after the halftime break and played with intent. As a floor general, he made plays for his teammates and dished out a couple of excellent dimes. He put up four shots in the penultimate period and made one while sinking both his attempts from the free throw line.The Mavericks' rookie sat out the entire fourth quarter as his maiden preseason campaign came to an end. Flagg will make his NBA regular-season debut on Oct. 22 when Dallas hosts the San Antonio Spurs at the American Airlines Center.