Biggio went 2 for 3 with a walk, drove in three and scored twice against the team his dad, Craig, starred with for 20 seasons. The elder Biggio has been a special assistant to Houston's general manager since 2008.
"I'm not going to lie, he definitely wants them to win but he wants me to do well," the younger Biggio said. "Last night was kind of the ideal scenario for him."
Cavan Biggio hit a solo homer in Friday's 7-4 Houston win, then connected in consecutive games for the first time Saturday as Toronto turned the tables on the AL West leaders.
"It's a pretty cool moment, not only for me but also for my family," said Biggio, whose parents have attended both games so far this series.
Houston has lost two of three after winning six straight and nine of the previous 10.
"We just didn't put together enough good at bats," Astros infielder Alex Bregman said.
Buchholz (1-3) allowed two runs and three hits in 5 2/3 innings, using four double plays to overcome a season-high five walks, including four leadoff walks.
"I would much rather walk a few of those guys than just give in and throw a fastball down the middle or hang a curveball," Buchholz said.
Houston finished with nine walks and had another runner reach on a hit by pitch. The Astros had more walks than hits (six).
"A lot of free baserunners to not be able to hit a ball in the gap or just find a hole," manager AJ Hinch said.
The victory was Buchholz's first since Aug. 22, 2018, with Arizona, when he pitched seven shutout innings to beat the Los Angeles Dodgers.
Buchholz said it was "mentally draining" working through Houston's deep lineup.
"I'm glad it's over," he said with a laugh.
Astros left-hander Framber Valdez (4-7) matched a career worst by allowing six runs and gave up a career-worst nine hits in 5 2/3 innings. Valdez has won just once in his past six outings.
"A mixed outing for him," Hinch said.
Bregman hit a sacrifice fly in the first, but Toronto scored three in the third. Randal Grichuk hit an RBI single and Hernandez, a former Astro, followed with his 21st homer.
Biggio hit a two-out blast in the fourth, his 12th.
Bregman cut it to 6-4 with a bases-loaded walk off Law in the seventh, but Buddy Boshers came on and struck out Alvarez looking to leave the bases full.
Astros: RHP Collin McHugh (right elbow) was placed on the 10-day injured list and RHP Jose Urquidy was recalled from Triple-A Round Rock. McHugh got the win Friday by recording the final out of the fourth inning. He threw 14 pitchers to two batters. McHugh missed 34 games because of elbow soreness in May and June. ... RHP Ryan Pressly (right knee) played catch in Houston Saturday, Hinch said.
KEEP WALKING, PART 1
Houston has drawn a major league-leading 19 bases-loaded walks this season. It's the most by any Astros team since 1974.
Toronto rookies have 169 extra base hits this season, breaking the 1977 team record of 167.
Astros: RHP Justin Verlander (16-5, 2.69) starts for Houston in Sunday's series finale. The AL ERA leader is 2-1 with a 2.51 ERA in five August starts.
Blue Jays: RHP Wilmer Font (3-3, 4.35) will open for the Blue Jays Sunday. Font is 0-1 with a 1.76 ERA in eight opening appearances, striking out 24 batters in 15 1/3 innings.
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