LOUDON, NH – Martin Truex Jr. mastered another Monday morning to win at New Hampshire Motor Speedway for the first time in 30 career Cup attempts at the same track where, as a child, he watched from the stands while his father was running.Thanks to rain postponements, Truex won his second Monday race of the season – he also won at Dover – and the fourth of his career.Truex dominated the No. 19 Toyota en route to his third victory of the season. The Joe Gibbs Racing driver scored one of the few victories he desperately wanted in a career…