MILWAUKEE -- The Giants opened the second half of the season by continuing to build off their recent offensive resurgence, hammering five home runs -- including a decisive 10th-inning grand slam by Buster Posey -- to fuel a wild 10-7 comeback win over the Brewers in Friday night’s series opener at Miller Park.

The Giants turned a one-run lead over to All-Star closer Will Smith in the bottom of the ninth, but the Brewers rallied to tie the game at 6 and force extra innings after reigning National League MVP Christian Yelich tripled and scored on a groundout by Mike Moustakas. It halted a run of perfection for Smith, who entered Friday 23-for-23 in save opportunities to start the season.

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Still, Smith wound up earning the win after the Giants mounted another rally against Brewers reliever Matt Albers in the 10th. With the bases loaded and no outs, Posey launched a first-pitch sinker from Albers out to center field for a grand slam that put the Giants ahead, 10-6. It was Posey’s fourth home run of the season and his first grand slam since June 24, 2015.

“It just shows it’s a team game to the max right there,” Smith said. “We give up the lead right there, and they come back and do their job, get the bases loaded with nobody out and Buster does his thing.”

All 10 of San Francisco’s runs came via homers. Austin Slater, Evan Longoria, Tyler Austin and Brandon Crawford each went deep for the Giants, who have now won seven of their last eight games. The Giants homered in each of the final three innings, as Austin and Crawford delivered solo shots off Brewers relief ace Josh Hader in the eighth and ninth, respectively.

“What was impressive is every home run was such a big one,” Giants manager Bruce Bochy said. “A couple of good comebacks. They came back, and it was a great game. It was good to see Buster give us a nice cushion there.”

The Giants’ offense ranked near the bottom of the league in virtually every major category in the first half, but their bats have started to come alive in recent weeks, imbuing the clubhouse with renewed energy and confidence. While the Giants remain six games below .500 at 42-48, they’ve gone 20-14 since June 1 and are now 4.5 games out of the National League Wild Card picture.

The widespread belief has been that the Giants will be sellers come the July 31 Trade Deadline, but the club’s players feel they still have time to change that narrative if they can sustain this level of success over the next few weeks.

“We’re not out of this thing by any means,” Austin said. “It’s a long second half, so if we continue to play well and win ballgames, we’ll be right there at the end of this.”

Career night for Anderson

Entering Friday, no pitcher had managed to strike out reigning National League MVP Christian Yelich three times in a game this season.

Rookie Shaun Anderson became the first to accomplish the feat, collecting three of his career-high eight strikeouts against Yelich. The 24-year-old right-hander became the first pitcher to strike out Yelich three times in a game since the Indians’ Carlos Carrasco on Sept. 2, 2016.

“He’s the best hitter in baseball right now, and my focus was dialed in when I was facing him,” Anderson said. “I wanted to make sure he didn’t beat me tonight.”

Anderson struck out the side in the fifth, but he was removed from the game after allowing the first two batters he faced in the sixth to reach base. He was charged with four runs on six hits over five-plus innings in his 11th career start.