By Mark Lamport-Stokes LA QUINTA, California, Jan 17 (Reuters) - Four days after winning his maiden PGA Tour title, American rookie Russell Henley made light of a fatigued start to the week as he surged into contention at the Humana Challenge on Thursday. The fresh faced 23-year-old fired an eight-under-par 64 on the Nicklaus Private course at PGA West, ending an ideal day for scoring just one stroke behind his pace-setting compatriots Jason Kokrak, Roberto Castro and James Hahn.