CLEVELAND -- During the Nationals' 9-4 victory over the Indians on Sunday afternoon, right-hander Stephen Strasburg experienced problems on the mound.

The game had to be delayed twice -- in the fifth and sixth innings -- because Strasburg was often slipping whenever he threw a pitch. In fact, catcher Ivan Rodriguez was the first to tell home-plate umpire Brian O'Nora that Strasburg was having problems starting in the second inning. O'Nora asked Strasburg if that was the case and Strasburg said he was fine.

"I said to [Strasburg], "Hey, if you need the mound to be fixed, just let me know. I'm not a mind reader,'" O'Nora said. "I said, 'Pudge said you are having problems.' He said, 'I'm OK.'"

However, before the fifth started, Strasburg acknowledged to O'Nora that the mound had to be fixed. An inning later, the Indians' grounds crew came and fixed the mound again. No other pitcher who threw that day had problems.

The sixth turned out to be Strasburg's worst inning. After getting Shin-Soo Choo to fly out, Strasburg allowed a single to Carlos Santana and walked the next two hitters he faced -- Travis Hafner and Austin Kearns -- before leaving the game in favor of right-hander Drew Storen, who was able to get out of the inning.

Strasburg lasted 5 1/3 innings, allowed one run on two hits, struck out eight batters and walked five.

O'Nora said Strasburg's long stride on the mound was the reason he had problems. His right foot often landed on the end of the pitcher's mound.

"He has such a long stride. I bet you it [was a lot] compared to the Indians. It's almost down to the end," O'Nora said about the 6-foot-4 Strasburg.

Said Strasburg about the mound: "I was just slipping a little bit, but there are going to be games like that. I was on the mound like that in college. I wasn't able to make the adjustments that I needed to do.

"I wish I could have handled it a little bit better. It kind of got me in a little funk. But it's good to experience this now. Those are the little things I'm trying to learn, and I'm trying to improve to where if it happens again, I will make the right adjustment."