Bernard Tomic admitted he had been "slacking off" following his 3-6 6-3 6-4 6-4 defeat by wildcard David Goffin in the Wimbledon first round on Tuesday.
The Australian teenager enjoyed a shock run to the quarter-finals last year as an 18-year-old, but on his return to Wimbledon's lawns was overwhelmed by a fresh-faced Belgian opponent.
"To have talent is one thing, it's huge for any sport," 20th seed Tomic told a news conference.
"But I have sort of slacked off a little bit and look what it's costing me. Last eight, nine weeks I'm losing a lot of first, second rounds. So it's not my quality of tennis.
"My quality of tennis should be getting me to a lot of semi-finals, finals at tournaments or even winning, but lack of concentration, not working hard, it costs you."
Tomic played well enough in the first set but Goffin roared back, bringing his inspired Roland Garros form to the grass courts on his Wimbledon debut. The Belgian reached the fourth round in Paris as a lucky loser.
"Well, look, he's 21. I'm 18, 19. I've gotten into the top 30," said Tomic. "It's different. He has time and he's going to obviously be a top-30 player. He has great groundstrokes.
"But I think what I've lacked the last few weeks is the consistency and it's tough to get."
Tomic will get an early chance to return to Wimbledon when he plays in the Olympic Games which start next month.
"I'm really lucky for that opportunity to have the Olympics coming up, which is, from my point of view, bigger than Wimbledon," he said.
"For any athlete I think it's something that I want to do well in and I'm thankful it's on grass."