Caleb Simpson scored five as Poly eased to a 12-5 lead by the start of the final period. A late goals rush by Manchester was never likely to affect the result.
But it's Penguin who top the table after the opening weekend. A 13-8 victory over Cheltenham confirmed Penguin (their Sheffield team is pictured above) as the only team to take maximum points from their two games. Andre Savic, Dennis Linde and Tilemachos Pissas all scored twice as Cheltenham were outplayed 7-2 in the opening period.
In one of the best games of the day, Sheffield built an early 7-2 lead against Watford but ended up under pressure to hold on to the points with a 17-15 win.
Watford twice cut Sheffield's advantage to a single goal as Jarad Baker scored with a long shot to leave his side 12-11 in arrears; then Adam Heywood's neat goal brought Watford up to 13-12. It was only at that point that Sheffield broke clear again with strikes by Chris Armstrong, Connor Carpenter and Corrran Bradley.
Earlier, Welsh Wanderers defeated Sutton & Cheam 15-7.