MLB playoff openers saw the White Sox, of whom the pope is a lifelong fan, defeat Houston 6-3 and Riley's homer in the eighth inning giving the host Braves a 5-3 victory over Philadelphia.
The White Sox posted on social media an inspirational letter received Tuesday from the leader of the world's 1.4 billion Catholics.
"I willingly invoke the Almighty's abundant blessings upon you and your loved ones," the pope wrote to White Sox owner Jerry Reinsdorf.
Divine intervention or not, the White Sox dominated to seize a 1-0 lead over the host Astros in the best-of-three American League wildcard series, with the winner to face Cleveland in the divisional round.
Wildcard series openers later find Boston at the New York Yankees in the AL and the Chicago Cubs at San Diego in the NL.
At Houston, the White Sox took the lead in the first inning when Sam Antonacci walked, reached third on an error by Astros first baseman Christian Walker and scored on Munetaka Murakami's sacrifice fly.
Astros starting pitcher A.J. Blubaugh was replaced by Bryan King after 2/3 of an inning and the White Sox took advantage.
Chicago's Braden Montgomery and Chase Meidroth singled to open the second inning, Colson Montgomery was hit by a pitch to load the bases and Antonacci followed with a two-run single to left for a 3-0 lead.
Kyle Teel singled to reload the bases and King was lifted for Miguel Ullola, who got three outs without allowing another run.
Colson Montgomery's solo homer in the fourth gave Chicago a 4-0 lead and Meidroth's bases-loaded single in the fifth made it 5-0.
Houston's Nelson Velazquez smacked a two-run homer in the fifth.
The Astros' Bennett Sousa allowed a Sox run on a wild pitch in the seventh but an error by Chicago third baseman Miguel Vargas in the eighth allowed a run for Houston to create the final margin.
The Astros, 5-2 against the White Sox this year, qualified for the playoffs on the season's last day and at 81-81 had the worst record of any post-season team in history.