A trio of seeds suffered early exits on day one of traditional Wimbledon warm-up, the DFS Classic in Birmingham.
Koukalova (above) was dispatched inside an hour by American Jackson
World number 36 and 10th seed, Klara Koukalova, was beaten 6-4 6-1 by American teenager Jamea Jackson.
Slovakian Martina Sucha converted seven out of 19 break points to comfortably dispatch Colombian 11th seed Catalina Castano 6-3 6-1.
American Laura Granville, who was seeded 16th at Edgbaston, then crashed out 6-4 6-4 to China's Zi Yan.
The only seed to survive in the early matches was Swedish number one Sofia Arvidsson, who beat Hungarian counterpart Melinda Czink 7-5 4-6 6-3.
British number four Sarah Borwell beat fellow Briton Melanie South 7-6 3-6 6-3 to also go through.
The top eight seeds in Birmingham have all been awarded second-round byes and will play on Tuesday.
Two-time defending champion and world number four Maria Sharapova heads the field, although she is continuing to struggle with an ankle injury.
Veteran Martina Navratilova withdrew from the doubles competition on Sunday.