Stephen Curry was bringing the ball up the court midway through the second frame. Warriors forward Draymond Green set a screen on Seth Curry, who spun around Green and raced after his older brother.
Steph Curry, unaware that the Blazers guard was chasing after him, continued to attack the hoop. Seth Curry extended his left hand and ripped Steph for the steal.
Later in the second, Seth Curry got the best of his brother again with a 3-pointer. Blazers point guard Damian Lillard tossed a pass to Seth Curry along the wing, and he stepped into a three. Seth Curry ignored Steph's hand in his face and found the bottom of the net.
Stephen Curry had 19 points on 6-of-10 shooting in the first half. Seth Curry tallied seven points in 15 minutes off the bench.
The Trail Blazers held a 65-50 lead at halftime. Golden State holds a 1-0 series lead over Portland.