Schiavone, seeded fifth at the All England Club, crumbled in the final set as she suffered her second opening round exit since clinching the first grand slam title of her career at Roland Garros earlier this month.
The Italian's Parisian triumph was one of the most surprising outcomes at a grand slam for many years and she still seems to be suffering the hangover from her celebrations after the final victory over Sam Stosur.
Schiavone lost to Sorana Cirstea in the first round at Eastbourne last week and fared no better in her second match since the French Open as the gritty Dushevina fought back from a set down.
Initially it seemed Schiavone would prevail as she took the first set tie-break without dropping a point.
But that whirlwind effort seemed to take it out of the 29-year-old, who turns 30 on Wednesday.
She began to look tired in the second set and when Dushevina took it there was only going to be one winner.
Dushevina is ranked 56th in the world and has never been past the second round at Wimbledon, but the 23-year-old held her nerve superbly to claim one of the best wins of her career in two hours and 54 minutes.