The defending champion overcame a slow start, from 0-3 in both sets, to challenge the 31st-ranked Kerber but she could not hold her serves and had to exit the competition after an entire day’s play was washed out by rains on Friday.
The 34-year-old Thai capitalised on just three of her 15 break-point opportunities in the one-hour 34-minute match.
Ranked 84th in the world, Tamarine is likely to slip out of the top 100 next week as she failed to defend her points after winning the title last year.