ATLANTA — Rookie right-hander Tanner Houck struck out 10 in another dominant performance, Christian Vazquez capped a big inning with a grand slam, and the Boston Red Sox routed the Atlanta Braves 8-2 Saturday night. Giving the Red Sox reason to be hopeful after a dismal season, Houck (3-0) surrendered his first earned run in three big league starts but thoroughly stifled baseball’s most explosive offense. Boston did all its scoring in an eight-run second capped by Vazquez’s second career grand slam. The 24-year-old Houck surrendered only three hits, walked three and held the Braves scoreless until Dansby Swanson led off the fifth with his 10th homer. Marcell Ozuna and Adeiny Hechavarría had the only other hits off the right-hander, who turned it over to the bullpen after throwing 94 pitches in six innings.