The Leeward Islands bowled out Guyana Harpy Eagles for 186 runs to win their 2nd round West Indies Championship match by 273 runs.
Rahkeem Cornwall took 6 for 71, while Daniel Doram took 2 for 48 as Guyana fell for 186 in 84.3 overs.
Tagenarine Chanderpaul top-scored with 47 while Veerasammy Permaul got 30 for the defending champions.
Guyana drew their first match against T&T Red Force and now faces an uphill task to retain their title after a chastening loss to the Leeward Islands.
The three other matches in Round 2 were completed on Friday.
T&T Red Force beat West Indies Academy by 6 wickets, Windward Islands beat Barbados Pride by nine wickets, while Jamaica Scorpions whipped the Combined Campuses and Colleges by 10 wickets.
The third round of matches in the West Indies Championship begins on Wednesday.
West Indies Championship – 3rd Round
Leeward Islands Hurricanes vs T&T Red Force – Warner Park
West Indies Academy vs Guyana Harpy Eagles – Coolidge
Jamaica Scorpions vs Barbados Pride – Sabina Park
Windward Island Volcanoes vs CCC – Chedwin Park