Up 11 goals at half-time, the Blues were poised for an easy road to the grand final and a date with Nathalia on Saturday.
“The girls just treasured the ball,” Tongala coach Abby Pettifer said.
“That was our main aim for the day was just to make good choices with the ball.
“If you’ve got the ball, you’re the one in charge. If someone leads too early, just be really vocal and talk to each other.”
But Mulwala had a response after the break.
Having scored 23 in the entire first half, the Lions went at 17 a quarter down the stretch and led twice in the final three minutes, but the sides finished regulation tied at 57.
Pettifer encouraged the Blues to refocus and take over in the overtime period.
“We really got sucked into their game,” she said.
“The two Stephs, their goalers, were the ones who were the playmakers and I just said to the girls sternly that we go back to our style of netball, short and sharp, and that we need to look after the ball and get it into our goalers.
“Chicky Vick was on fire and her fitness really showed as well.
“It was pretty much pull your fingers out and get back to our style of netball and treasure the ball and they did exactly that and ended up running away with it.”
Whether Tongala rediscovered itself during the break or Mulwala was simply spent from its second-half heroics, it was the Blues who dominated the overtime period.
The Lions were held to three goals in the first half of extra time, and Tongala had a five-goal cushion, which it only extended in the second stanza, escaping with a 72-65 victory.
The Blues advance to Saturday’s grand final at Moama, where they will battle minor premier Nathalia.
The Purples have dropped a single game this season, which was to now-eliminated two-time premier Rumbalara, and will be favoured in the clash after winning by 20 and nine goals in two previous meetings with Tongala.
“We are good enough and I think the girls have real belief now,” Pettifer said.
“They know that we’re really meshing at the right time of the season.
“We were all new playing together and it takes a little bit to get there.
“They might be a champion team on paper, but you need to make sure that you can actually work together.”
The first meeting of the year came in round one, where Tongala was still finding its footing as a new squad, and the Blues shaved 11 off that margin in the later clash on June 6.
“As a math teacher when you do the math we cut it by 11, if we can cut it by another 11 after playing again that's two up,” Pettifer said.
“Anything can happen, the girls are in a good mindset and we are out to have a crack and just to do our best.
“Our aim was to make the grand final, it is a big aim, and we’ve done that and gone one better than last year.”
Tongala reached the preliminary final in each of the past two seasons after winning the 2023 flag.
Nathalia’s Jane Cook will be a threat in goal shooter, the Purples’ only loss coming with the league’s second leading goaler not present.
“Our aim is just to beat everyone else on the court and not worry too much about Jane in goal shooter,” Pettifer said.
“Obviously she’s the biggest target in the league and our aim is just to make sure that we’re doing our job everywhere because in the end we’re going to get the same amount of centre passes as they do.
“That’s always going to be even, so we just need to convert and hopefully the girls can work hard, show their fitness and we can pick up a few of those intercepts before they even get down to the goal ring.”
The A-grade grand final will conclude the action on the netball courts on Saturday, and is scheduled for 2pm.