Last week he felt like a heavyweight boxer, but now Bernard Tomic feels light on his feet and ready to cause some Australian Open damage.
Stung into action by barbs about his weight following a first-round loss to David Ferrer at the Brisbane International, Tomic went to work before revealing a chiselled frame at the Fast4 exhibition event in Sydney.
The upshot was a six-pack - which he happily showed off - and impressive five-set win over Open dark horse Dominic Thiem, the world No.8 and top seed for this week's Sydney International.
"I needed it because I played a bad match in Brisbane so I needed to take it seriously, and Dominic did as well," Tomic said.
"We were focused. We were wanting to grab the competition out of this.
"So I'm happy with how we played, regardless of the format. It was high quality tennis from both of us."
The 196cm Tomic, who towers over most opponents, admitted he opened the summer "a little bit overweight" after "resting and eating" while recovering from an abdominal strain.
"I was about 99 kilos, as opposed to 94," he said.
"So as I started to doing a lot of fitness, I gained a little bit more strength and I was a little bit slow around the court.
"In one week I trained well, I did the right things, I watched my diet and I'm feeling pretty good now.
"You can say last week I was fat. I was.
"I mean, I am tall. I am big - but 99 kilos, close to a hundred, is too much."
Tomic will wind up his Open preparations at the Kooyong Classic exhibition event starting on Tuesday.
But after reaching the fourth round at Melbourne Park for the third time last year, Tomic has dropped from a career-high world No.17 to 26th and will miss an all-important top-16 seeding.
The 24-year-old admits he'll be somewhat at the mercy of Friday's draw.
"I can play obviously the top eight guys (in the third round)," he said.
"Obviously a few of those top guys I've beaten - Stan (Wawrinka), Kei (Nishikori) and (Marin) Cilic.
"So I've got matches there I can win and I've got a good record against them.
"Obviously the top three, I don't have a good record (against) - (Milos) Raonic, (Andy) Murray and Novak (Djokovic)."