His team down by a point at half after trailing by as many as 15 on Friday night against the Lakers, Spurs coach Gregg Popovich dispatched an altered lineup to start the second half. In for Danny Green was Manu Ginobili. In for Boris Diaw was Matt Bonner. “We sent some messages to people who weren’t playing good D,” Popovich said. “In the second half, we got that straightened out.” In Popovich’s mind, the Spurs’ improved second-half defense was a prime factor fueling the Spurs’ 91-85 victory over the Lakers. Los Angeles, of course, was without star Kobe Bryant and struggled for answers on offense. Aside from Pau Gasol, who broke loose for 20 points and 11 rebounds, the Spurs handled the rest of the Lakers’ starting five. The Lakers’ starting backcourt of Steve Nash and Steve Blake were a combined 3 of 20, including 2 of 10 from 3-point range.