With another win Monday, the Spurs' veterans can take the remainder of the regular season off.
Ginobili scored 20 points Sunday to lead San Antonio to its seventh straight victory, 114-98 over the Cleveland Cavaliers.
San Antonio (47-16) moved 1½ games ahead of Oklahoma City, which lost to the Lakers earlier Sunday, in the race for the best record in the Western Conference. A victory in any of their final three games would secure the top spot in the West for the Spurs, who own the tiebreaker over the Thunder.
Ginobili said the Spurs were keeping an eye on the Lakers' double-overtime victory before their game. San Antonio hosts Portland on Monday.
"We want to clinch as soon as possible," Ginobili said. "Tomorrow we have a good game here, so we're going to be trying to play our best and keep improving. We have room for improvement, where we can pick up the aggressiveness. We want to try and set the pace for the playoffs."
Cleveland (21-42) lost for the fourth time in its last five games despite the Spurs giving Duncan the night off. With the playoffs right around the corner, the 35-year-old Duncan was the only active Spur not to play.
Stephen Jackson scored 17 points for the Spurs, DeJuan Blair added 15 points and seven rebounds, and Danny Green had 14 points. Antawn Jamison led Cleveland with 21 points, Kyrie Irving had 19, and Manny Harris added 14.
"I thought it was a relatively sloppy game, but we managed to keep our lead," Spurs coach Gregg Popovich said. "Sometimes in the NBA that's hard to do. We stuck with it and got the win."
Besides limiting Duncan's minutes this season, Popovich has given his star forward six nights off to rest. Thanks to another easy victory, their other veterans didn't play too much.
Ginobili and Parker each played just 22 minutes. The Spurs entered the game having won four straight games by at least 21 points. During that span, Ginobili has played 30 or more minutes only one time, and Parker has done so just twice.
"Any time we get a chance to rest Tim and Tony doesn't play that much, and we get away with a win, that's always a plus," Jackson said. "As long as we take care of business and continue to build and not take steps back, we'll be all right."
Parker had six points and nine assists for the Spurs, who swept the season series.
"When you have three Hall of Famers on one team, it's tough to beat them," Irving said. "A lot of people are downplaying them just because their age is up there a little bit. But they're still one of the best, if not the best, teams in all of basketball."
One of those potential Hall of Famers, Ginobili, showed off his full arsenal of plays, hitting layups, runners and step-back jumpers. The veteran forward was hampered by injuries earlier this season, but he's now looking like the Ginobili of old.
"For sure, I'm feeling better than a month ago," Ginobili said. "That's promising, and that makes me feel good and in a better mood."
The Spurs led only 52-44 at halftime behind 11 points from Green, but the starting forward left the game in the second quarter after a flagrant foul by Harris. Green was hit in the left eye by Harris while going up for a layup with 5:35 left in the second quarter. Green stayed on the ground for several minutes before getting up to hit one of two free throws. He then left for the locker room for the rest of the quarter before returning for the second half.
Spurs F Boris Diaw started for Duncan and had six points on 3-of-7 shooting. ... Scott ranked third-lowest in a poll of players when asked which coach they would most like to play for, finishing ahead of Orlando's Stan Van Gundy and last-place Scott Skiles of Milwaukee. "The thing I know about both those guys is they're pretty demanding guys," Scott said. "So if that's the case, and I'm put in that category as being a very demanding coach, I don't mind that. You've got a lot of guys that want you to kiss their butts. I'm not doing that. That ain't happening. And I'm not going to tell them all the time what they want to hear." Popovich ranked third-highest.