Mark Wegner, the home-plate umpire in Tuesday’s game between the Boston Red Sox and Houston Astros, admitted to missing a call in the bottom of the fifth inning that should have resulted in a Cam Smith strikeout, but he instead walked later in the at-bat.

Speaking to reporters after the game, Wegner admitted he has “never done that before” when addressing the mistake.

“I’ve never done that before. I’m not happy about it,” said Wegner. “Just made a mistake.”

The mistake occurred when Houston had runners on the corners with two outs. Smith swung at the second pitch of the at-bat against Red Sox starter Brayan Bello, with Joey Loperfido breaking from first to second.

Red Sox catcher Connor Wong bounced the throw into second base and the ball scooted away from Marcelo Mayer, allowing Christian Walker to score from third.

After the play, Bello asked for the count and Wegner signaled it was 1-1 when it should been 0-2.

“I asked him because I thought the first pitch was a strike, and then I thought that he swung at the second pitch,” Bello said to reporters through an interpreter after the game. “But none of that took me out of my focus on that inning. I tried to get out of that inning, but it didn’t happen.”

The play-by-play summary of the game on MLB.com has the correct result of the pitch, which was a swing. It lists the count after that as being 0-2 and the next pitch was a swinging strike that should have ended the at-bat and inning.

Instead, everyone on both teams reacted as if it was a 1-2 count at that point. Smith eventually worked a nine-pitch walk, even though the official game tracker on MLB’s website shows the result as being three balls and six strikes.

Bello was taken out after that plate appearance and replaced by Ryan Watson, who got out of the inning by getting Yainer Diaz to ground into a forceout.

Even though it’s little comfort to the Red Sox given they lost the game 9-2, the final result from Smith’s at-bat didn’t end up costing the Red Sox a run, though the inning had already gotten away from Bello by that point. Houston scored three runs in the frame and put up six total against Bello, who was charged with five earned runs in 4.2 innings.

Houston improved to 4-2 to start the season after Tuesday’s win. The Red Sox, meanwhile, have lost four straight since their season-opening win over the Cincinnati Reds.

The two teams will close out their three-game series from Daikin Park on Wednesday at 2:10 p.m. ET.