* Woods secures decisive point for U.S. * Americans win Cup for an eighth time * Lead Internationals 18-14 overall (Adds detail, quotes) By Mark Lamport-Stokes DUBLIN, Ohio, Oct 6 (Reuters) - The United States won the Presidents Cup for the eighth time on Sunday, beating the Internationals 18-1/2 to 15-1/2 at Muirfield Village Golf Club after Tiger Woods clinched the victory by beating South African Richard Sterne. With the Americans needing a total of 18 points to retain the trophy, Woods secured the decisive point by safely parring the final hole of his singles match. ... More...