Bolt, who reached a career-high ranking of world No.125 last March, took it to the two-time French Open runner-up before falling 6-2 5-7 6-7 (5-7) 6-1 6-2 on Thursday.

Thiem was glowing in his praise of Bolt post-match, saying the South Australian didn't have any clear weaknesses.

"There is not a single reason why he shouldn't get to the top 100 soon," the Austrian said.

The boy from Murray Bridge said the "compliment" meant a lot coming from "one of the best players in the world".

"He's one of those guys that are fighting for slams," Bolt said.

"If I keep going along this path that I'm going on, I think the top 100 is well in reach."

Bolt, 27, looked on course to score a stunning upset as he battled to a two-sets-to-one lead.

But fatigue became a factor as his body began to feel the residual effects of Tuesday's five-set victory over Spain's Albert Ramos Vinolas in the first round.

"Probably mid-way through the third (set) my energy level started to drop a little bit," he said.

"I just sort of hung on in that third set and then it was downhill from there."

Similar to Australian No.1 Ashleigh Barty, Bolt took a nine-month sabbatical from tennis in 2016 and worked as a tradie in that time.

His self-imposed break now makes moments like going toe-to-toe with Thiem as well as blasting a memorable round-the-net scorcher in the third set - one of the shots of the tournament thus far - all the sweeter.

"It was probably the best decision that I've made in my life," Bolt said.

"Not just tennis but in life in general. I just got a lot of perspective on things in life.

"Now that I'm back I don't take anything for granted. I just try and soak everything in and enjoy every time out there on court."

Australian Associated Press