Watson's three wickets included that of Yuvraj Singh, whose struggles against short-pitched bowling are well-known.
"That's a plan everyone has tried to attack him with and get the short balls in," he said.
Watson, whose 133-run opening stand with Warner broke their own national record, said Australia's bullish start to the tournament proved the team's best cricket was capable of winning it.
"That's what we came here for, to take that next step. We've still got a long way to go."
