The fourth pitch to David Ortiz in the bottom of the 11th inning on Saturday afternoon was a slider that bounced past catcher Jason Castro.

Xander Bogaerts, who was on first base, jogged to second.

The Houston Astros had a decision to make at that point: Continue to pitch to Ortiz with two outs, or walk him with first base open and take their chances with Hanley Ramirez.

The complicating factors were myriad. The pitcher was Michael Feliz, a 22-year-old rookie righthander who had never faced Ortiz before. But he had a 2-and-2 count on Ortiz, an advantage situation for the pitcher.

Still, this was Ortiz. At 40 he remains one of the game’s best hitters and has made a career of delivering game-winning hits. He had already tied the game with a triple in the ninth inning and hit a home run in the third.

Castro went to the mound to talk it over with Feliz. Their plan was to pitch to Ortiz, but not give him anything to hit.

“It’s kind of hard to not take two waste pitches, which is what Castro went out to tell him,’’ Astros manager A.J. Hinch said.

Watching from the dugout, Red Sox manger John Farrell expected the Astros to intentionally walk Ortiz, or least throw two pitches well off the plate.

“We were a little surprised. They might look to expand the strike zone. If they walk him, OK, they’ll face the righthander on deck,’’ Farrell said. “That’s their decision.’’

The next pitch was a belt-high changeup on the outer third of the plate. Ortiz drove it to the base of the wall in center field, the ball striking to the left of the 420-foot marker.

As the sold-out crowd erupted, Bogaerts scored and the Red Sox had a thrilling 6-5 victory.

Ortiz’s teammates swarmed him at second base and tore off his jersey. Joe Kelly, looking for a unique means of celebration, liberated a cup of flour from the clubhouse kitchen and threw it at Ortiz.

“David is amazing. I don’t care if he’s 100 years old. I’m not letting him beat me at 100,’’ Jackie Bradley Jr. said. “We’ll take it.’’

Ortiz dressed quickly after the game to attend the birthday party of his daughter, Alexandra, and did not speak to reporters.

“Just say I’m a bad [expletive],’’ Ortiz shouted on his way out.

It was the first time in his career Ortiz had a double, triple, and home run in the same game.

“You know Papi’s going to be sore tomorrow because of that,’’ Ortiz told WEEI from the field after the game.

Ortiz walked off the field carrying second base as a memento. The double was the 600th of his career. In major league history, only Hank Aaron, Barry Bonds, and now Ortiz have at least 500 home runs and 600 doubles.

“It feels good,’’ Ortiz said. “Hitting is the toughest part of the game. Being able through the years to produce and here in my last season being able to help this ballclub is something I work extremely hard on.’’

Ortiz is hitting .320 with 10 home runs and 33 RBIs. In what he still promises is his final season, Ortiz has been at his best.

“We travel to all these ballparks and he’s presented gifts. But I think our fans are getting the greatest gift of all, and that is seeing what David is doing game in and game out,’’ Farrell said.

“What David is doing, it really is incredible to watch daily.’’

The 23-14 Red Sox have won six of seven and 11 of their last 15 games. They have scored 63 runs in the last six games.

“The moment that we are living right now, it’s something very special,’’ Ortiz said. “Something that gives me some really good thoughts and hopefully continues through the year.’’

The ninth inning started with the Red Sox down, 5-4, and facing Houston closer Luke Gregerson.

Bradley, who earlier extended his hit streak to 20 games, drew a one-out walk. Bogaerts then grounded into a force at second base.

That brought up Ortiz. He lined a fastball to center field that tailed away from Jake Marisnick and one-hopped the wall. Bogaerts scored easily and Ortiz steamed to third for his 19th career triple, the first since 2013.

With a chance to win the game, Ramirez inexplicably decided to bunt. He pushed the ball meekly in front of the plate and was thrown out to end the inning.

“He saw something maybe only he saw,’’ Farrell said.

Ramirez called reporters over to his locker after the game and defended his odd decision.

“I just needed a base hit to bring Papi home,’’ he said. “Everyone was playing back. If I get it down, he would have scored.’’

Red Sox starter Clay Buchholz struggled again. He allowed five runs, four coming on a grand slam by George Springer in the second inning. Carlos Correa had a long home run in the first.

Buchholz has allowed five earned runs in five of his eight starts and has an earned run average of 6.11.

Houston starter Collin McHugh allowed four runs on 10 hits over six innings.

Bogaerts had an RBI double in the first inning. Another run scored when Travis Shaw drew a bases-loaded walk.

Ortiz homered in the third inning, his 10th of the season and No. 513 in his career. Josh Rutledge doubled and scored on a Mookie Betts ground out in the fourth inning.

Red Sox relievers Carson Smith, Tommy Layne, Junichi Tazawa, Craig Kimbrel, and Koji Uehara (2-1) combined on five innings of shutout relief.

In the joyous postgame clubhouse, Bogaerts was asked about the decision to pitch to Ortiz. He had the best view of the situation, after all.

“It was going by so quick I never even thought about walking him with first base open. I never even thought about it,’’ he said. “After the game, I was like, ‘Ooooh, maybe they should have.’?’’

Peter Abraham can be reached at pabraham@globe.com. Follow him on Twitter @PeteAbe.