Spalding shines for Peterlee.
The Seaham side were restricted to 90-7 in their 20 overs, N Holmes making 37.
Niall McGoldrick proved the most effective bowler on the visitors' side, taking three wickets for just seven runs to keep the Dawdon batsmen in check.
Peterlee then made light work of the run chase, rattling off the required runs with more than three overs to spare and losing just two wickets in the process.
Joe Spalding produced the stand-out performance, making a superb unbeaten 51 to inspire his team to their emphatic success.
Bill Quay were just as outstanding in their game at Seaham Harbour, restricting their opponents to 85-6 and then knocking off the required runs for the loss of only one wicket.
It was essentially an allround team effort for the Quay, Tom Huckle headlining in the run chase with an unbeaten 30.
Wearmouth turned in a top-class effort to see off hosts Murton by 113 runs after making 137-3. L Richardson made 52 not out and S Doren 50 not out.