Luke Walton feels the Los Angeles Lakers are still lacking mental toughness after they "gave in a little bit" in a fourth-quarter collapse to the San Antonio Spurs. The Lakers (15-10) were on course to beat the Spurs (12-14) for the second time this week as they led 99-89 through 36 minutes, but they were outscored 44-21 in the fourth to slump to a tough defeat.