SAN FRANCISCO -- There is clearly no doubt about who has the overwhelming momentum in the National League Division Series. It's the Reds, and it's not even close.

After all, they earned an emphatic 9-0 win over the Giants in Game 2 on Sunday night that included one-hit baseball from starter Bronson Arroyo over seven innings. Cincinnati returns home with a 2-0 advantage in the best-of-five series only needing one win over the next three games to be held at Great American Ball Park.

For having one very successful business trip, the Reds kept the giddiness to a minimum and lacked for jubilation. They're not quite done with the Giants, definitely not yet.

"You're not comfortable at all until it's over," Reds manager Dusty Baker said.

"We couldn't put ourselves in a better situation. It doesn't mean you're going to close it out," said Arroyo, who walked one and struck out four. "I know the fans are going to be as jacked as they have ever been in that ballpark since it has been built, which is going to be nice. But that being said, we've got to calm it down a little bit and stay [with] the task at hand, because we haven't won anything, and baseball is a crazy game."

Even though they had home-field advantage, there were complaints about the NL Division Series setup this season. It meant the higher-seeded Reds had to play the first two games vs. the Giants on the road at tough AT&T Park.

Well, take that, dreaded 2-3 format.

"Obviously the most important [thing] was to get the first two wins," said right fielder Jay Bruce, who hit a two-run double during a five-run eighth. "This home field is interesting. Coming into this place, against this team, against this pitching, it's tough. We handled it well. Our pitching did an unbelievable job. You couldn't do any better than to go home up 2-0."

Play resumes Tuesday after a day off on Monday, but the Reds can feel good that history is overwhelmingly on their side. Since Division Series play began in 1995, the team with a 2-0 lead advanced 38 of 42 times (90 percent), and no team has blown it since 2003.

An NL team has had the 2-0 situation 21 times -- and has never lost the series.

"Now we still have to stay focused," left fielder Ryan Ludwick said. "There still have been four teams to come back from a 2-0 deficit in this series. We have to stay focused, go home, get some rest tomorrow because it's going to be a late flight. We'll get back after it on Tuesday."

Credit Arroyo for putting the Reds in this enviable position, as he simply owned the night. Arroyo retired his first 14 batters in a row, which included four straight strikeouts, until Brandon Belt lined a clean two-out single to right-center field in the Giants' fifth.

Before that, San Francisco hadn't sent a ball out of the infield since the first inning, when it had three straight fly balls. That was because Arroyo was mercilessly changing speeds and doing what he wanted.

"To get through the fifth inning without having to pitch from the stretch but one time was really big," Arroyo said. "It allows you to get in your groove."

Ludwick gave Cincinnati a 1-0 lead when he launched lefty Madison Bumgarner's first pitch of the second inning and watched it carry over the center-field wall for his first career postseason home run. Including the regular season, it was the 10th of his 27 homers to be hit on the first pitch. He also entered the night 1-for-16 lifetime vs. Bumgarner, who threw a one-hit shutout against the Reds on June 28.

The homer was the only Reds hit over their first 11 batters, but they certainly pounced in the top of the fourth, with four hits and three runs against Bumgarner.

Joey Votto started it with a leadoff single to center field, followed by Ludwick's lined single to center. Scott Rolen came through with a one-out single into medium right field. Waved around all the way from second base, Votto scored ahead of Hunter Pence's poor throw to the plate with a headfirst slide.

Next was Ryan Hanigan's rolling single up the middle that scored two more runs and opened a four-run lead. The Giants turned to a deposed ace in former two-time Cy Young Award winner Tim Lincecum, who pitched a sharp two scoreless innings. It only slowed the Reds' locomotion temporarily.

With breathing room, Arroyo kept the Giants quiet as he mixed offspeed pitches in any count. In getting Gregor Blanco to look at strike three on a full-count pitch to begin the third, Arroyo dropped into a sidearm delivery.

Following Belt's hit, Arroyo retired seven of his final eight hitters and exorcised some demons vs. the Giants. He hadn't beaten them since Aug. 31, 2008, and was 0-2 despite a very respectable 2.42 ERA in the four starts since.

It became a blowout in a five-run top of the eighth, during which the Reds sent nine to the plate and sent several of the 43,505 fans seeking the exits. Cincinnati had its highest-scoring playoff game since Game 3 of the 1995 NLDS against the Dodgers, when it completed a sweep with a 10-1 win.

Not a bad result from a team that was last in the Majors with only 83 runs from Sept. 1 through the end of the season, an average of 2.86 runs per game. Since clinching the NL Central on Sept. 22, the Reds scored four runs in a game only twice in the final 10 games. Now they have 14 runs after two playoff games.

"Our offense kind of slowed down there towards the end of the season," Ludwick acknowledged. "I think you tend to see that sometimes when a team clinches as early as we did. When you get in the postseason and those lights turn on, it's a different game."

Now, the Reds are one win away from reaching the NL Championship Series.

"The job is not finished yet," second baseman Brandon Phillips said. "It's going to be a long flight home, but I'm going to be smiling on the plane, I'll tell you that."