Pat Cummins said Pakistan's late fightback with the bat was a warning for the reigning champions even though his side managed to get a 41-run victory at Taunton.
This was Australia’s third win of the tournament following their loss against India.
Pakistan were reduced to 200-7 at one point but a 64-run partnership between Sarfaraz Ahmed and Wahab Riaz provided Aussies with some worrying moments.
"It goes to show that everyone can bat these days," said Cummins. "It was a bit closer than we would have liked, so it was good to get those couple of wickets and finish it off.
"We gave them a bit too much width and suddenly they were back in the game," the 26-year-old added. "It's a good lesson to learn."
Cummins removed Fakhar Zaman early and then had Imam-ul-Haq caught behind off a short ball.
But the significant improvement in Cummins’ bowling is the high percentage of dot balls which increases pressure on the opposition batters.
"That's the big improvement in my game in the last couple of years, the ability to hold a length and make it difficult to get runs," Cummins explained.
"If you give away easy singles then 300 becomes quite an achievable score. Cutting out the singles is huge, it means if you give away a boundary it might not be that big over of 10 or 11, it may just be a five or a six."
Earlier, David Warner scored his first international hundred since his return to cricket after a year-long ban for his involvement in ball-tampering scandal last year.
He was back to his best against Pakistan after struggling to keep up the scoring rate against India at The Oval.
"We were so pumped for him, he was really open and honest after the Oval game," said Cummins.
"He was playing more timidly than normal but we saw his mindset change from the start here."