Pakistan have hailed wicketkeeper-batsman Mohammad Rizwan as a "warrior" after revealing he was in hospital with a severe chest infection before taking the field to score a brave half-century in defeat to Australia at the T20 World Cup.

Rizwan top-scored for Pakistan with 67 from 52 balls in Thursday's semi-final in Dubai to help the south Asians post 176, but Australia reeled in the runs to reach Sunday's final against New Zealand.

Pakistan's team doctor said Rizwan was admitted to hospital on Tuesday and spent two nights in intensive care.

"He made an incredible recovery and was deemed fit before the match," doctor Najeebullah Soomro said.

"We can see his great determination and tenacity that shows his spirit of performing for the country. And we can see how he performed today."

Opener Rizwan showed no sign of illness, clubbing four sixes and three fours before falling to paceman Mitchell Starc.

Captain Babar Azam, who opened the batting with Rizwan, said the 29-year-old was a "little bit down" before the match.

"But when I asked him about his health he said, 'no, I will play'," said Babar.

During his innings, Rizwan became the first player to score 1,000 runs in T20 internationals in a calendar year.

Scoring 281 for the tournament at an average of 70.25, Rizwan is second only to Babar (303) on the World Cup runs list.

"This is a warrior," said Pakistan batting coach Matthew Hayden, the former Australia test opener.

"He has been brilliant through (the tournament) and he’s got great courage, as has Babar. Fantastic tonight from him."