In 2008 and 2009, Jon Lester emerged as one of the best pitchers in baseball. In 2010, however, he is reaching pinnacles that he never achieved in those two dominating years.

On Sunday, even though he was, in the words of manager Terry Francona, “sluggish,” Lester figured out a way to dominate a Royals club that has become a personal highlight reel. Against the franchise whom he no-hit in 2008 and tossed eight shutout innings of one-run ball in 2006, the left-hander logged seven innings and permitted just a single run on four hits in his club’s 8-1 victory.

In the process, the 26-year-old ran his career record against Kansas City to 4-1 with a 1.22 ERA, the second-lowest ERA of any pitcher (min. 5 starts) against the Royals behind Chad Ogea. More impressively, it ran his season record to 6-2 and his 2010 ERA to 2.97.

It marks the first time since his rookie season of 2006 that Lester has had a sub-3.00 ERA in a season. Clearly, he is enjoying status as one of the dominant young pitchers in the game. He is currently on one of the most impressive runs of his young career, as he is 6-0 with a 1.43 ERA in his last eight starts, including a 5-0 run in the month of May that established a new high for most wins in a single turn of the calendar.

Those numbers have made a distant memory of the left-hander’s slow start, when he went 0-2 with an 8.44 ERA in his first three outings. But, Lester insists, it did not take his current run to allow that deliberate start to fade from memory.

“You can sit here and dwell on the past, and you’re not thinking about your next opponent,” said Lester. “Those starts were behind me the day after I started those games. I’m not too concerned about it, nor will I be concerned about it if I do it again. I know what I’m capable of, and I just have to get on a roll, get some confidence and the rest will take care of itself.”

The same could be said of his performance against the Royals. Through the first 2 1/3 innings, Lester was fighting his mechanics, resulting in command issues. He walked three and allowed two hits before recording his second out of the third inning. He got to 59 pitches through the first three frames, and it appeared that he might struggle to work deep in the game.

But after a walk put runners on the corners with one out in the third, Lester found his form. He struck out Kansas City’s two best hitters (David DeJesus and Billy Butler), commencing a run in which he retired 10 straight hitters.

“I think sluggish is the best word [to describe his performance] early, but he fought through it and did a terrific job,” said manager Terry Francona.

As a result, Lester was able to take satisfaction in going seven innings and getting a win in a game where it appeared he might struggle to last even six innings. It marked the sixth time in seven outings that he has gone at least seven frames.

“That’s our job, to find a way to go deep in the game,” said Lester. “Early on, it was a battle. And it still was a battle through the middle innings, but I was able to get a couple one- and two-pitch outs. that always saves your pitch count when you get a couple of those. … I started pounding the zone better. Guys started hitting the ball on the ground. It makes the game a lot easier.”