LOS ANGELES >> Young Lawson Walton sang "Happy Birthday" to his father, and Lakers rookies Brandon Ingram and Ivica Zubac offered the same greeting to their coach at morning shootaround on Tuesday.Luke Walton appreciated all the warm wishes, then reality set in hours later when the 37-year-old Lakers coach watched his young team crumble down the stretch for another loss - outscored by 24 points in the fourth quarter of a 119-108 setback to the Washington Wizards at Staples Center.