The American, who came third at the recent J-Bay Billabong Pro at Jeffrey's Bay in South Africa, ended five days of action at Long Beach with victory over Hairil Anwar of India.
In one- to three-foot waves, Lau posted a score of 14.50 to Anwar's 11.90 to take the win at the four-star ASP event.
"Glory to God!" he tweeted after winning the event. "All things are possible through he who strengthens me."