LOS ANGELES -- Jake Peavy is excited about the chance to put his mark on the most vibrant rivalry in baseball. He told San Francisco Giants beat reporters earlier this week, "I'm not going to lie to you. I was just in the shower thinking about Dee Gordon."

Peavy, it's seems safe to assume, was thinking about how to get Gordon out, but the Los Angeles Dodgers had a little fun with it. Adrian Gonzalez, who played with Peavy in San Diego, took a picture of the Dodgers' speedy leadoff hitter in a towel holding a bottle of shampoo and texted it to Peavy.

Starting Monday, the fun and games are over and by 7:05 p.m., the jocularity between the teams will be, too. The Giants are desperately trying to claw their way back in the division race to avoid the perilous wild-card path to the World Series, and the Dodgers are intent on clinching the division some time over the next three days, then celebrating in front of their rivals for the first time in 10 years.

"If we clinch against them, of course that'd be great," said veteran pitcher Dan Haren, who will oppose Peavy on Monday. "I've been clinched on many times and it's not a good feeling. So, it'd be something fun to do against your rival, that's for sure."

The teams have circled each other on the schedule all season, but the pivotal point -- at least from the perspective of the moment -- was the late-July series at AT&T Park. The Dodgers had lost seven of 10 head-to-head matchups and were trailing by 1½ games going into it. They were coming off mediocre series at St. Louis and Pittsburgh, but they rose to the occasion and played one of their best series of the year behind their three best pitchers. They won all three games and haven't spent a day outside first place since.

Because the Dodgers swept that series, the only thing they have to do is avoid being swept in this series, it would seem. They go into it with a 4½-game lead with only three games left after it against the last-place Colorado Rockies.

"I didn't pitch that series, but the feeling in the clubhouse was that we needed to sweep them and we did," Haren said. "We understood the magnitude of the series even a few months ago and now we've played good enough baseball to put ourselves in a really good position. We don't have to go out and sweep them or do something crazy. We just have to play good."

The fear of disaster, though, is never far away from a team trying to lock up its postseason positioning, especially not for its manager, who is inevitably blamed for his team's failings. Should the Dodgers and Giants somehow finish in a tie, they would play a 163rd game on Sept. 29, most likely at AT&T Park, even though both teams are assured of postseason berths. Dodgers manager Don Mattingly said he thought about the magnitude of this series as far back as last season, when the 2014 schedule came out.

"When you see the schedule and you see those games are there and you know what kind of club they have, I think you feel like those games are going to be important, they're going to count," Mattingly said. "I think it's better for baseball and better for the fans. I think everybody likes seeing those matchups. There's a history there. It's good for the fans to see two quality organizations butting heads. You never know what happens. I think the energy level is always going to be up when you play them. I think that's just natural and I don't think you have to push that, especially when they're meaningful games."

Just as they did in July, the Dodgers tweaked their rotation to get their three best pitchers in line to face the Giants. They withstood a "bullpen game" Sunday in Chicago so that Haren could pitch Monday night. With Hyun-Jin Ryu out because of a sore left shoulder, Haren has emerged as the Dodgers' No. 3 starter. If Ryu can't pitch in the playoffs, Haren figures to play a big part of the Dodgers' World Series push. He hasn't been to the postseason since 2006, when he was 26 years old and playing with his second of six teams, the Oakland A's. He's eager for the chance to contribute.

"They had asked me how I felt about it and I'd like the opportunity to pitch against them, so I was excited," Haren said.