United States coach Adam Krikorian had to apologise to his team after a tactical error forced the Olympic women’s waterpolo semi-final against Australia into extra time on Tuesday night before the Americans won 11-9 to advance to the gold medal match.

Leading 9-8 with only seconds to go, Krikorian called a time-out, mistakenly believing that his team had possession, which resulted in an automatic penalty shot for the other side.

Australia’s Ashley Southern converted the penalty to send the match into the extra periods before the US scored twice to progress to their second successive Olympic final.

“They came over and I said, ‘my bad’,” Krikorian said of his error. “When you mess up, you’ve got to own up to it.

“I was feeling horrible. There’s thoughts that go through your mind, man, I might have blown this one (but)... nothing will break this team.”

The American players said they had been unfazed by their coach’s error.

“We looked at each other and said ‘we’ve been through this before’. Nothing’s going to affect us,” teenager Maggie Steffens said.

“We’re going to be the team that finishes this. We knew that whatever it came down to, we’re going to keep fighting,” said Steffens, whose huge goal-tally has made her the darling of the team in her Games debut.

The semi-final, a replay of their clash at the same stage in Beijing, was intense with numerous tussles between players and the maze of visible red scratches on arms and chests evidence of the rivalry between the best two sides in the world since the women’s competition was introduced to the Olympics in 2000.

“They’re definitely our biggest rival. Every game against the US you know you’ve got to come up with a battle,” Southern said.

Having disposed of their closest rival, the Americans will now face Spain, who had the better of Hungary 10-9, in today’s final.