The Australian, ranked No 4 in the world, was swept out of the Adelaide men's hardcourt tournament in the second round, beaten 7-5, 6-4 by the 64th-ranked Czech.
"The last two years have been very difficult, so it has been hard to get motivated and do the work again," Rafter said after being bundled out of his first tournament back from a two-month lay-off with a knee injury.
Rafter said he had tried to maintain his training during the break but had been losing focus under the weight of his playing commitments and recent fame. "It was really hard to push," he said. "I've got to find that motivation over the next week leading up to the [Australian] Open."
Rafter has his sights on the top ranking this year, and had his hopes boosted by the withdrawal from the Melbourne grand slam event of current No 1, Pete Sampras.
However, the 26-year-old admitted to feeling the pressure of public life after his back-to-back US Open wins and rise up the rankings. Success has seen him plastered as a sex symbol on magazine covers worldwide and he is continually mobbed by fans.
Rafter said the constant attention was a small price to pay for his success, but was tough to handle nevertheless.
"I'm confined to the hotel a lot because I just don't want to deal with people all the time. People are being nice but at the same time it's hard for me to be nice all the time," he said.
Rafter was sluggish on court against Dosedel yesterday, being frequently passed at the net by the Czech right-hander.
The defending champion, Australian Lleyton Hewitt, advanced to the quarter-finals, completing a 7-6, 2-6, 6-4 win over another Czech, Jiri Novak.Reuse content