St George captain Nick Stapleton has capped a fine individual season with a stunning unbeaten century to help lead Saints to an epic victory over Mosman in their final match of the season.
The win launched St George up to seventh, two points outside the finals places.
After being sent in at Hurstville Oval on Saturday, Stapleton enjoyed a 120-run opening partnership with Luke Bartier (50) and a 100-run stand with Test batsman Kurtis Patterson (38).
Stapleton hit 23 fours and launched four sixes to finish 170 not out from 166 balls as St George reached 4-313 from their 50 overs.
It was Stapleton's third century of the season and his highest score. It was also the highest ever score for St George in limited overs cricket, surpassing Patterson's 167 not out set earlier this season.
The young all-rounder scored 986 runs across 22 innings in all three formats at an average of 51.9. That included 771 runs in first grade at 64.3.
He also took 22 wickets with the ball.
Rain saw Mosman lose six overs, leaving them a reduced total of 288 runs to win in 44 overs.
Needing to win to have a chance of making the finals, Mosman captain Scott Rodgie put the visitors in the game with 156 from 132 balls at the top of the innings before he was bowled by Stapleton.
Mosman required four from the last ball to snare a tie but failed, leaving them stuck on 8-283.
While Saints fell just short of the finals in first grade, St George will host Gordon at Hurstville Oval in their fourth grade qualifying final this weekend after finishing second.