With two on and two out, Pence drove a ball to deep right field that appeared to hit the top of the fence and bounce back in play. Pirates right fielder Steve Pearce fired the ball back to the infield as Pence reached second base.
"As an outfielder, no matter what, play it and maybe the umpire won't see it, that's what I tried to do," Pearce said. "The ball was hit very well. It looked like it hit the very, very top of the wall. It was so close that I just wanted to get it back in. It hopped right back to me, and I just wanted to get it fired in.
"I like the replay system. Home runs are hard enough to come by, so I think it's something good where you don't get robbed of a home run you actually hit."
Astros manager Cecil Cooper came out to argue with first base umpire D.J. Reyburn. As many in the crowd of 30,034 voiced their displeasure with the initial call, Reyburn then met with the other three umpires -- crew chief Tim Welke, plate umpire Bill Welke and second base umpire Chris Guccione -- before the decision was made to go down in the tunnel and review the play on a television monitor near the visiting dugout.
"[The umpire] said he thought it hit the top, the yellow line," Cooper said. "I just said I thought it was a home run. They conferred and he decided they'd go take a look."
After about two minutes, crew chief Tim Welke returned and signaled that the initial no-homer call would stand. Pence was awarded with an RBI double.
The ball has to clear the yellow line to be a home run. Otherwise it's in play.
Welke said the umpires decided to go to the replay because it was so close.
"We wanted to make sure we got it right, and the replay confirmed that we got it right," he said.
The process went about as smooth as could be expected.
"It was quick. It didn't delay the game too much," Pirates manager John Russell said.
"I guess it's a good thing, worked about like you'd think," Houston first baseman Lance Berkman said. "They went in there, looked at it, saw it was the right call and came back out and said it was the right call. I mean it was pretty cut and dry."
Umpires can utilize video replay to determine a contested home run for these three reasons: fair or foul, in or out of the ballpark and fan interference.
All televised MLB games are monitored and staffed by an expert technician and either an umpire supervisor or a former umpire at Major League Baseball Advanced Media headquarters in New York. A television monitor and a secure telephone link to MLB.com, placed next to the monitor, have been installed at all 30 ballparks.
If the crew chief determines that instant replay review is necessary on a particular disputed home run, he calls the MLB.com technician, who then transmits the most appropriate video footage to the crew chief and the umpire crew on site. The umpire supervisor or former umpire does not have direct communication with any of the umpires on site, and the decision to reverse a call is at the sole discretion of the crew chief. The standard used by the crew chief when reviewing a play is whether there is clear and convincing evidence that the umpire's decision on the field was incorrect and should be reversed.
"The guards got out of the way and closed the door and [plate umpire] Bill Welke and myself had privacy and the technician had the three or four replays that we saw right away," Tim Welke said. "We were able to confirm what we saw on the field, and that's why we left it in play."
Pence said he had no idea where the ball hit but was pleased with the process.
"Those guys are great at what they do and they got the call right," Pence said. "I was pretty grateful when I was out there that they wanted to make sure they got the call right. I was kind of indifferent on [instant replay] until a situation came up where it could change things, and now I think it's a great thing for baseball and I can't say enough about those guys."
Tim Welke also thought the process worked well.
"Here in Houston, it did," he said.
Jim Molony is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.