Many were wondering what the injury-prone 25-year-old was doing in the Caribbean while he missed three comfortable victories with a left calf-muscle injury sustained while bowling against Bangladesh last month in Antigua.
However, he demonstrated both his fitness and his form heading into Wednesday's semi-final against South Africa in St Lucia with a hard-hitting 65 not out in the 215-run trouncing of New Zealand with which Australia wrapped up their Super Eights campaign.
The Black Caps, who looked like restricting Australia to around 300, instead saw Watson power the double-defending champions to 348 for six.
They had no answer to his blistering 32-ball innings featuring four sixes and four fours.
Watson then took one for 20 with his brisk medium-pacers as New Zealand were bowled out for 133, the Black Caps suffering both their heaviest one-day international defeat and the largest inflicted upon a Test team at a World Cup.
"It might quieten a few people down, particularly back at home, that have been casting all these doubts around about Shane Watson and his value to this team," said Ponting.
"You are not going to see striking like that from somebody who can't play the game," added the captain of Watson, who was opening the innings before Matthew Hayden was recalled to the one-day set-up.
"He's done everything in his power to get back in the side and his performance was first-class. He looked good with the ball as well and felt no pain whatsoever, so it's a very encouraging come back for him.
"Shane Watson is a very talented cricketer and someone who works extremely hard at his game,"
"He hasn't had a great run with injury over the last couple of years but if you have a look at his form in the one-day side, he's hardly put a foot wrong.
"It's great to see somebody that works as hard as he does, gets the results from his game."
Watson has played just three Tests, injuring his shoulder in his third appearance in Brisbane in November 2005 against the West Indies.
He made his one-day international debut in 2002 but his 63-game career in the shorter format has also been interrupted by fitness problems.
Chosen for the 2003 World Cup squad, he withdrew because of a back injury and had to withdraw from Australia's one-day squad that toured Bangladesh 12 months ago because of a right calf strain sustained while making 201 in the domestic Pura Cup final.
He then missed the whole of Australia's recent 5-0 home Ashes triumph against England with a hamstring problem.