Lewis saw off Toni Alcinas with the Spaniard missing three match darts to dodge a bullet.
Jenkins eased past Ross Smith so it was an easier assignment than Lewis as he made his return to the European Tour.
Thornton battled past Robert Marijanovic coming from 5-3 down to claim a 6-5 win showing the former multiple major champion is still in business.
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Evening session schedule
Martin Schindler (81.63) 6-4 (82.51 Justin Pipe
Michael Rasztovits (90.62) 6-4
(88.88) David Pallett
Jermaine Wattimena (84.71) 5-6 (86.4) James Wilson
Adrian Lewis (87.29) 6-5 (87.17) Toni Alcinas
Terry Jenkins (85.41) 6-3 (78.08) Ross Smith
Robert Thornton (87.15) 6-5 (82.78) Robert Marijanovic
21:15 Ricky Evans v Danny Noppert
21:45 Cristo Reyes v Nico Blum