The co-hosts, chasing Pakistan’s modest 213 all out, were reduced to 59 for three in the 11th over before they recovered to post a six-wicket win in front of a packed house of 47,000 at the Adelaide Oval.
Steve Smith (65) and Shane Watson (64 not out) swung the match around with a fourth-wicket stand of 89 and Glenn Maxwell smashed an unbeaten 44 off 29 balls as Australia won in the 34th over.
Watson hit the winning boundary after a tense start to Australia’s chase saw left-armer Wahab remove David Warner and Clarke in his first two overs.
But two dropped catches, both off Wahab’s bowling, cost Pakistan dearly.
Watson was on four when he hooked a bouncer high to fine-leg where Rahat Ali got under the ball but dropped the catch.
Wahab, who later returned for his second spell in the 29th over, almost removed Maxwell with his second delivery, but Sohail Khan at third man failed to hold the top-edged pull.
“That spell by Wahab was as good as any I have faced in one-day cricket after a long time,” Clarke said.
“Left-armers are always tough to face for right-hand batsmen because the ball comes on to you.
“If that catch off Watson had been taken, who knows what would have happened. This game would have been closer for sure.
“Fast bowling definitely played a part in this game for both teams. If Watson’s catch had been taken maybe Pakistan’s 213 may have been enough.
“But credit must go to the way we found a way to see through that spell. There was a bit of luck but it also showed Watson’s experience.”
It emerged later that Watson and Wahab would face charges after their fiery confrontation which saw tempers boil over, words exchanged and the Pakistani even sarcastically applauding the batsman for playing and missing.
“Shane Watson and Wahab Riaz charged for breaching ICC Code of Conduct. Details to be announced on Saturday,” tweeted the game’s governing body.
Clarke said the loss of early wickets did not worry him.
“No, I was not worried by that start,” he said. “That’s the way the game goes when there are two new balls. Thankfully, we have depth in the batting.”
Clarke praised the batting contributions of Smith, Watson and Maxwell, but said the win was set up by Josh Hazlewood’s four for 35 that restricted the Pakistani batsmen.
“I think all our bowlers deserve credit, especially Josh who claimed four important wickets,” he said. “It really was a good job by all.”
Australia’s eighth consecutive win over Pakistan on their own soil set up an enticing semi-final clash against defending champions India at the Sydney Cricket Ground on Thursday.
Clarke said he was looking forward to the challenge against India, who bounced back from a winless Test and one-day tour of Australia prior to the World Cup to win seven World Cup matches in a row.
“The fact that we move on gives us confidence,” he said. “We have been improving slowly and every win gives you momentum.
“India and Pakistan have different strengths and weaknesses. India have been here for a long time and have worked out the conditions.
“We have time to recover and prepare. And we look forward to the challenge on Thursday.”
Clarke paid rich tributes to Pakistan’s veterans, captain Misbah-ul Haq and all-rounder Shahid Afridi, whose one-day careers ended after the defeat.
“They have been fantastic, experienced players,” he said. “Misbah is a good leader and Boom-Boom Afridi is a one of a kind, a real entertainer.
“We have had some tough challenges in the past. I wish them both well in future.”