The ACT Aces left it to the last over of the day to grab the third spot in the Plan B Men's Regional Big Bash finals after an outstanding round of T20 cricket in Wagga Wagga on Sunday.

The Aces join Newcastle Blasters and Lake Mac Attack in next year's four-team decider on the SCG after winning back-to-back games to claim Thunder Pool two honours.

The fourth finals place will be decided between Orana Outlaws and Illawarra Flames on November 29.

The Blasters will meet the Attack in one semi-final, with the Aces taking on the winner of the Outlaws-Flames showdown in the second semi.

The Aces won through to the final with a comfortable win over Murrumbidgee Rangers followed by a tense victory against Wagga Wagga Sloggers in Wagga.

Murrumbidgee won the toss and batted first against ACT but found the going tough.

The Rangers lost wickets at regular intervals and could only cobble together a modest 113 after being bowled out on the last ball of their 20 overs.

The Aces were rarely troubled, reaching their destination in the 17th over thanks largely to opener Josh Myburgh's 38 and an undefeated 45 from Rhys Healy.

The easy win was in stark contrast to the other conference game between Border Bullets and the Sloggers.

That went down to the penultimate delivery after the Bullets set their hosts a challenging 144 to win.

The Sloggers were 6-112 before Warren Clunes (32 not out) and Ethan Perry (seven not out) dragged their side across the line with a ball to spare.

It would be the first of two very tight contests for the boys from Wagga Wagga.

Perhaps flattened by the excitement and tension associated with the earlier win, the Sloggers were bowled out for just 97 on the first ball of the 20th over in the follow-up game against ACT.

Surely that would not be enough against the in-form Aces?

Think again.

Early wickets to the Sloggers' David Garness (2-11) and Hamish Starr (1-16) – plus a run out – had the Aces in disarray at 4-37.

Josh Staines (38) and Tyler Van Luin (28 not out) then came together to repair the damage, putting on 46 for the fifth wicket.

Van Luin, who had earlier captured 3-26, and Scott Murn (seven not out) took the game into the last over before securing a hard-fought victory.

Scores click here