The former French Open champion and world number 16 slumped to a 6-1 6-7 6-2 defeat and said a troubling toe injury may force her to miss the opening grand slam of the season, the Australian Open starting in Melbourne on Jan 15.
Myskina, playing for the first time since October, received treatment during the second set and looked ill at ease throughout her one hour, 51 minute defeat.
''I realised during the match that I may not be ready for the Australian Open,'' she told reporters.
''I still feel pain there and it bothers me. Maybe I'm going to take a longer break.'' Myskina later told officials she would be returning to Moscow for treatment and would skip next week's Sydney International.
The 21-year-old Dulko eased through the first set in 24 minutes but missed a match point opportunity when she served leading 6-5 in the second.
Myskina, champion at Roland Garros in 2004, broke back and then took the tie-break, but Dulko always looked the sharper around the court and duly wrapped up victory and a place in the second round against American Jill Craybas.
Marion Bartoli came through the first match in the defence of her title, the Frenchwoman disposing of 16-year-old Japanese Ayumi Morita 7-6 6-3.
Reuters SAM GC1404