Two of the people who know David Warner best say they are the least surprised by his emphatic bounce-back for Australia at the T20 World Cup.

The 35-year-old opening batter struggled to make his mark on the Indian Premier League season and was ultimately cut loose by the Sunrisers.

His formline did not bode well for the World Cup, where the Aussies were hoping he could play a major role in their tournament in the UAE.

The veteran struggled in the warm-up games, but has since whacked scores of 65 against Sri Lanka and then 89 not out against the West Indies to signal a return to form.

His 89 off 56 balls against the Windies sounds an ominous warning to Australia's semi-final foe, Pakistan.

Warner's wife, Candice, says her husband was always going to prove the doubters wrong. "He's come good at the right time. With the semi-finals... let's hope he can repeat that performance," she told 2GB radio.

"The one thing we know about David Warner is you never write him off. It's almost like if he is in a bit of a form slump, or he's out of runs, sometimes you need someone to spark that fire, to doubt him or tell him he's too old, he's not fast enough anymore, and fire him right up.

"That's what it's done, and let's hope tonight we can see a really explosive performance with the whole Australian team."

Warner's long-time T20I opening partner, Aaron Finch, can't believe critics were essentially sounding the alarm and suggesting his international career was coming to an end.

Finch joked about how physically fit Warner is at the moment. "I don't see him with a shirt on much these days. He never used to take it off, but now he never puts one on," he laughed.

"He walks around and he flexes. He thinks he's Connor McGregor walking around here sometimes.

"It was great to see him dominate the Windies the other day. He's such a wonderful player, has been for a long period of time. One of Australia's great all-time batsmen over all three formats of the game.

"The confidence he's had the whole time has been there. I can't understand how people write him off after two or three low scores, it blows my mind."