Fellow American Wayne Rainey, world champion and second in the current standings, increased the pressure on Schwantz in the final qualifying session yesterday by taking pole position.
Rainey, riding a Yamaha, produced the fastest lap time of 2min 2.448sec on the 5.39km (3.34 mile) Masaryk circuit. Schwantz leads Rainey by three points, 192 to 189.
The Australian Mick Doohan, on a Honda, was second fastest in 2:02.804 and the American veteran John Kocinski returned to 500cc action on a Cagiva by taking third position in 2:03.152.
They were followed by the Italian Luca Cadalora on a Yamaha in 2:03.163 and Schwantz on a Suzuki in 2:03.210. Rainey, a three-time world champion, and Schwantz have turned this year's championship into a two-man battle.