(Reuters) - Rejuvenated by improved form with his driver, Zach Johnson made a strong start to his title defense at the John Deere Classic in Silvis, Illinois as he surged into a share of the early lead in Thursday's opening round. The 37-year-old American piled up seven birdies in a flawless display for a sizzling seven-under-par 64 at the TPC Deere Run, finishing joint top with Colombia's Camilo Villegas. ... More...