Glendermott, after a season of frustration and disappointment, won the game that mattered to preserve their place in the top flight of North West cricket.
The Londonderry side went to Coleraine — their rivals for relegation — and pulled off an eight runs victory.
Charlie McCrum, the former Ireland international, batted through their 45 overs innings, but finished one short of his century as Glendermott totalled 196 for five. Coleraine were in pole position at 115 for one after 30 overs with Mohammad Salman still at the wicket.
The Pakistani had scored 140 of his side’s 260 in the league game at the Rectory in July, but the lack of help was to cost the Bannsiders dear in their final game of the season.
When Salman was lbw to Rodney Pierson for 75, Coleraine were just 27 runs from victory — and safety — but four more wickets fell for 17 runs and Coleraine head straight back to Senior Two after their season in the limelight.
They will be replaced next year by St Johnston, the Donegal side sealing promotion with victory over Burndennett on Saturday.
The battle between Limavady and Strabane for the Senior One title goes to 20/20 action this week after the rest of the weekend programme was washed out. Dates to be confirmed.
Ireland Under-19s got their World Cup Qualifying campaign back on track on Saturday with a 73 runs win over previously unbeaten Papua New Guinea.
After their shock defeat to the United States the previous day, Paul Stirling (57 off 59 balls) and James Shannon (46) returned to form with a third wicket stand of 84, but it was Graham McDonnell’s superb 62 from just 34 balls including 11 boundaries which allowed Ireland to total 273 for six.
PNG raced off at more than six an over in their reply, but McDonnell, the Pembroke all-rounder, then took three wickets in four overs to reduce them to 98 for four. Wickets fell regularly and the Islanders were all out in the 44th over.
The win takes Ireland back up to second place in the nine-team tournament, level on points but ahead on run-rate, with PNG and their next opponents, Canada, whom they play today.
It was the batting which let Ireland down against the Americans.
Although the bowlers took only five wickets, as the USA totalled 217 for six, it should have been a straightforward chase for Ireland, especially after captain Andrew Balbirnie (45) and Lee Nelson (33) had put on 62 for the first wicket, but the next highest partnership was 25, for the ninth wicket as Eddie Richardson attempted to end with a flourish, and Ireland were bowled out in the 47th over for 175.