With a little more than four minutes remaining in the third quarter and Detroit leading 61-55, the 6-foot-3 Johnson attacked off the dribble from the left wing, rising high for the left-handed dunk over the top of the 6-foot-10 Ohlbrecht. The thunderous finish drew oohs from the small crowd and brought Houston's bench to its feet.
Johnson, 21, was selected in the second round of last month's draft by Houston with the No. 42 overall pick. The 2014 Pac-12 Player of the Year averaged 16.3 points, 4.1 rebounds and 2.8 assists per game for the Arizona Wildcats.
Ohlbrecht, 25, went undrafted in 2010. The German center spent most of the last two seasons in the D-League.
Johnson finished with 18 points (on 7-for-14 shooting), five rebounds and three assists against the Pistons. Chris Crawford paced Houston with 20 points (on 8-for-13 shooting).
Kentavious Caldwell-Pope led all scorers with 26 points (on 8-for-19 shooting), four rebounds and one assist. Peyton Siva added 16 points (on 4-for-8 shooting), six assists and one rebound in the win.
The Orlando Summer League will continue through July 11. The Las Vegas Summer League will then pick up from July 11-21.