Manager Bo Porter challenged the safe call, which was confirmed. Gentry wound up scoring the tying run on an Eric Sogard single.
"Once I took a look at it, you look at the leverage of the play, if he is out, obviously, it clears the bases," Porter said. "If not, the tying run is now on second base. So we felt like it was a good challenge."
In the bottom of the ninth, with the Astros trailing, 5-3, Jose Altuve hit into a double play but nearly beat the throw at first base. Porter, who couldn't challenge the call following the Gentry play, asked for a review; an umpires review confirmed the call.
Chris Carter followed with a solo homer to cut the lead to one run before Dexter Fowler lined out to end the game.
"Obviously, my eyes are not too good," Porter said. "I thought Altuve beat that play, but replays showed that he didn't. It's tough, but C.C. continues to swing a hot bat."
Brian McTaggart is a reporter for MLB.com and writes an MLBlog, Tag's Lines. Follow @brianmctaggart on Twitter. This story was not subject to the approval of Major League Baseball or its clubs.