Penrith Cricket Club couldn't have written a better script or ending to their disappointing season with all grades except fourths posting wins in the final round against Sydney on Saturday.

The club's best under-21 players backed up on Sunday to come home with the shield after a win against favourites StGeorge at Hurstville Oval.

The hosts elected to bat first and were bowled out for 146 from 50 overs.

Pat Cummins bagged three wickets while Josh Jones and captain Tim Sutton grabbed two each.

``A sigh went through the ranks when the boys lost two early wickets in their run chase,'' club secretary Ross Graham said.

``Being 2-20 down created a few moments of brief anxiety.''

An 81-run partnership between Sutton (35) and man of the match Jordan Silk (58) steadied the ship as their side cruised to victory with seven overs to spare and six wickets in hand.

All five senior grades missed their respective Sydney cricket finals.

Sixth grade are in the quarter-finals of Metropolitan Cup, which start this weekend.

``The PG Shield win has laid the platform for next season,'' Graham said.

``After's last year's club championship title, the retirement and loss of several senior players meant we knew this would be a tough season and it impacted greatly in all grades.

``This was a rebuilding year, which will possibly continue into next season.''

Meanwhile, Blacktown fifths were the only grade to win against Sutherland, while sixths also made the Metropolitan Cup finals.