Kansas City, Mo. ? Mark Teahen erased a night of mistakes with one swing of his bat.

Teahen had a throwing error, a base-running blunder and could have been charged with a second error on a hard-hit ball that was ruled a single. Nevertheless, his tiebreaking two-run home run in the eighth carried Kansas City to a 6-4 victory over Pittsburgh on Wednesday night and sent the Royals’ third baseman home a happy and very relieved young man.

“I was hacked off the whole game,” he said. “I’ll definitely sleep a lot better tonight now than I would have earlier in the game. I’m just glad I was able to help out a little after hurting the team earlier.”

Teahen, whose throwing error had led to an unearned run, hit the first pitch from Salomon Torres (2-4) over the fence in right for his fourth home run, giving the Royals their fifth victory in seven games. Emil Brown started the inning with a single against the Pirates, who blew a 4-0 lead for the second night in a row and have lost seven straight.

“When you’re ahead 4-0 and have a lot of men on base, you really have an opportunity to break things up, and if you don’t take advantage, it’s going to make you pay,” said Pittsburgh manager Jim Tracy. “Our opportunity for the knockout punch was there and we didn’t take advantage.”

Ambiorix Burgos pitched the ninth for his 11th save in 17 opportunities, getting a game-ending double play grounder. Elmer Dessens (4-6) pitched 12â3 hitless innings for the win.

The Pirates are 1-7 against the American League.

“I’m disgusted with myself,” said Torres. “I should have done my job. Unfortunately, when you don’t make the pitches at this level, they’re going to get hit. I’ll just try to go out and do my job next time, but with more intelligence.”

Pittsburgh starter Ian Snell cruised through the first five innings before Joey Gathright, making his first start in center one day after coming over in a trade from Tampa Bay, singled to ignite a four-run inning.

One out later, Mark Grudzielanek’s RBI single scored the speedy Gathright from second. After Doug Mientkiewicz walked, Brown had an RBI double, and Matt Stairs chased Snell with an opposite-field RBI single that made it 4-3.