SAN ANTONIO Keldon Johnson scored 28 points and the San Antonio Spurs defeated the short-handed Portland Trail Blazers 113-92 on Sunday night to strengthen their bid for a play-in berth. Coupled with the Los Angeles Lakers' loss to Denver, San Antonio's magic number for clinching 10th place in the Western Conference is two games. The Spurs (33-45) also hold the tiebreaker over the Lakers (31-47) with a better conference record.