With four rounds to play, the Blues’ 59-37 victory means they are five games clear of seventh-placed Finley, meaning they are guaranteed a finals berth.
But early on in the contest it looked like Tongala might have to wait another week before locking in finals, with United starting well and jumping out to an early seven-goal lead.
However, the Blues held their nerve and worked their way back into the contest, tightening the scoreline before steadily pulling away.
“It was a very slow start from us,” Tongala coach Paige Wade said.
“Echuca United started really well and we couldn’t have started any slower, I don’t think. They came out more ready than us. It was just a really slow start on our end.
“But we got ourselves back on track by the end of the first quarter, which was good. It was good that the girls stuck at it and we knew that our teamwork would prevail.
“For the rest of the game we played well and got the job done.”
Wade said Eesha Clarke and Grace Hammond were two of the standouts, while Milly Brock and Abbey Nexhip did well in the attacking third.
"It was one of Eesha’s best games of the season. She is starting to really play some nice netball after a couple of years off,“ Wade said.
“Grace Hammond played well. She went back into defence for us and did a good job. And Milly and Abbey shot and combined well in attack.”
With its top six status confirmed, Tongala will now have a chance to test itself against a potential finals opponent when it hosts Moama this weekend.
“We’re looking forward to the challenge. They are the games you play for, the ones that are going to be tight,” Wade said.
“Our last contest was reasonably close but we couldn’t stick with them for the whole game. We’ll be trying to put four good quarters together.”
For United, the loss means its finals hopes are all but extinguished. The Eagles are three games behind Mulwala in sixth with four rounds left to play and would need something just short of a miracle to reach the finals now.
The 10th-placed Eagles have had three wins and 11 losses this season.