SAN FRANCISCO -- His right hip "barking" at him, as he put it, 40-year-old San Francisco Giants pitcher Tim Hudson was reminded Monday night why he's planning to retire at season's end.

He then watched as six relievers attempted to postpone the party.

Hudson combined with his six mates to hold the Cincinnati Reds to seven hits, allowing the Giants to their fourth consecutive win, a 5-3 triumph in the opener of a three-game series.

Third baseman Matt Duffy, center fielder Angel Pagan and first baseman Brandon Belt had two hits apiece as the Giants built a 4-0 lead and held on for their fourth victory against the Reds this season in five head-to-heads.

"We're plugging along. We're playing good ball," Hudson observed after the Giants (76-68) remained 7 1/2 games behind the National League West-leading Los Angeles Dodgers (83-60), who won at Colorado.

Seeking team success ahead of personal glory, Hudson informed Giants manager Bruce Bochy of his ailing hip while the club was building an early 4-0 lead.

The disclosure eventually led to his early departure from the game -- two outs away from what could have been a career 222nd victory.

"I can't argue with it. We had to get out of the jam right there," Hudson said of getting pulled with a 4-0 lead, but with the bases loaded and just one out in the fifth inning. "We won the game. That's the important thing."

Hudson said the hip pain was "something a little ice and a little Advil will take care of." He insisted he was planning to make his next scheduled start, Sunday against Arizona.

"Time is dwindling down. I'm just excited to go out there and pitch," he said. "I see the finish line. I see it coming. It's time. I wish we were making the playoffs."

A two-run homer by Reds right fielder Jay Bruce off the fifth Giants pitcher, left-hander Josh Osich, got Cincinnati within 4-3 in the seventh inning.

But Giants right-hander Sergio Romo retained the one-run advantage with a 1-2-3 eighth inning, and closer Santiago Casilla escaped a two-on, no-out jam in the ninth for his 33rd save.

"That last game (a 6-2 win at Arizona), he pitched so well, and he hit that home run. Not bad for a 40-year-old," Bochy assessed of Hudson. "At the time, there was a question if he was changing his mind (about retirement). Maybe today he confirmed he's probably doing the right thing."

Hudson was charged with one run in his 4 1/3 innings. He allowed three hits and three walks, and struck out one.

The Giants gave Casilla a bit of a cushion by adding a fifth run in the bottom of the eighth, courtesy of a two-base error by Reds shortstop Eugenio Suarez and a sacrifice fly by Belt.

The RBI was the second of the night for Belt, who had a run-scoring triple in the Giants' two-run third inning against Reds starter Keyvius Sampson.

Duffy also had two RBIs on a two-run double in the first.

Sampson (2-5) was pulled from the game after the inning, having been roughed up for four runs (three earned) on five hits in three innings. He walked two and did not strike out a batter.

Four of the five hits he allowed went for extra bases.

"This game has a way of not only showcasing your strengths but pinpointing your weaknesses," Reds manager Bryan Price said of his rookie pitcher. "He would get ahead and then make a mistake on a two-strike pitch, or fall behind and have to come in with something."

Right-hander George Kontos (3-2), the third Giants pitcher, was credited with the win despite having faced just one batter in the fifth inning.

The win was the Giants' 25th in their last 33 home games.

Catcher Ramon Cabrera had four of the Reds' seven hits, including a double. He singled to open the Cincinnati seventh and scored ahead of Bruce's homer, his 21st of the season.

Following an inning-opening single by Suarez, Cabrera also singled in the ninth to put the potential tying runs on base with no outs.

But Casilla struck out pinch-hitters Skip Schumaker and Tucker Barnhart, then got Bruce to line out to the warning track in right field to end it.

"I wish I could have done more," Bruce said. "I got a good pitch to hit (in the seventh against Osich) and I didn't miss it. I missed a couple of others."

Coming off a 5-5 homestand that included three wins over the first-place St. Louis Cardinals, the Reds (60-83) were playing the opener of a nine-game trip.

NOTES: Giants 3B Matt Duffy's two doubles in the game gave him 26 for the season, the most for a San Francisco rookie since 1B Will Clark and 2B Robby Thompson each hit 27 in 1986. ... Reds CF Billy Hamilton left the game in the fifth inning with a sore right shoulder. ... The Reds are scheduled to start three rookies -- RHP Keyvius Sampson, LHP John Lamb and RHP Michael Lorenzen -- in the series. At the other end of the spectrum, the Giants' starters Monday and Wednesday -- RHP Tim Hudson and RHP Jake Peavy -- have 31 years of major league experience between them. ... Giants manager Bruce Bochy disclosed before the game that 2B Joe Panik had an MRI on his sore lower back Monday and likely is out for the season.