Two weeks after declaring he lacked any dedication to tennis, Nick Kyrgios has pledged to fire up for Australia's bid to reach the Davis Cup final.

Australia play Belgium in the semifinal in Brussels this weekend, looking to secure their first trip to the decider since their 2003 win over Spain.

An injury-hampered Kyrgios bowed out of the opening round of the US Open with an assortment of fines, a smashed racket and a tantrum, while burnishing his reputation as the tour's most talented slacker.

"I'm not dedicated to the game at all," he told reporters at Flushing Meadows, describing an off-court regimen of milkshakes, ice creams and walk-up basketball games.

"There are players out there that are more dedicated, that want to get better, that strive to get better every day, the one-percentres. I'm not that guy."

Following on from his admissions of video game marathons at a previous tournament, it was another confessional to elicit groans back home where exasperated fans still hope the 22-year-old can knuckle down.

In Davis Cup, they can at least be confident of something approaching a full-blooded performance from Kyrgios, who loves the team aspect of the competition and played a leading role in Australia's quarterfinal victory over the United States in April.

Kyrgios's commitment to the tournament has grown in importance since Bernard Tomic, the country's other half-hearted talent, has crashed out of the top 100 through a combination of missing tournaments and not training very hard.

"Davis Cup has done wonders for me this year," Kyrgios said.

"It's really made me find that love again for just being with the guys and having some fun, knowing that tennis isn't all bad, knowing that you can have some fun with it."

Kyrgios will spearhead Australia's charge against a strong Belgium team featuring world number 12 David Goffin.

The last time Australia reached the final, Lleyton Hewitt, the current team captain, was in his prime and fittingly, he will oversee the country's best chance of adding to its 28 titles in over a decade.

Former world No 1 Hewitt, a revered Davis Cup servant in Australia, has been credited for bringing out the best in Kyrgios.

"'Rusty' (Hewitt) has helped me a lot," said Kyrgios.

"I think he's the best captain we've ever had. I know that everyone on our team would run through a brick wall for him.

"To take home the trophy would be probably a dream come true for me."