As Lynnfield girls tennis teams go, coach Craig Stone says this one’s constructed a little differently.”Usually,” he says, “there’s not a big dropoff in talent between our No.1, No. 2 and No. 3. There’s balance.”Not so this year. The 20-0 Pioneers, who go into their state semifinal game Monday (either 3 or 3:30 at Lexington High) against Cohasset/Dover-Sherborn with the distinct advantage of having, possibly, the states No. 1 player in Sarah O’Neil.”She’s going to be competing in the state individual championship next week,” he says, “and we’ve never had anyone like that before.”So in that sense, there’s a bit more of a dropoff between No. 1 and No. 2 than usual.”O’Neil is undefeated at 19-0. But just so that nobody thinks that there’s nothing supporting her, No. 2 singles player Allison Bodek is also 19-0, and the No. 1 doubles team of Tara Soni and Julia Broding are also unbeaten (16-0).This year, the Pioneers have had their share of 3-2 wins (including the North sectional final over Manchester-Essex), but, as Stone says, a win’s a win.”Our other players are very good too,” he said. “Tori Copelas a third singles and our second doubles team (Julie Hambrecht and Alicia Leone) have also contributed a lot.”Stone admits not knowing a lot about Monday’s opponent, but he also says it doesn’t matter.”You have to play to yourself,” said Stone, who also coaches the Lynnfield wrestling team. “and you have to play to win.”The important thing,” he said, “is to stay focused and play within what we like to call ‘the zone.’ If you let everything else bother you, that’s when you have all these peaks and valleys in your game.”Stone knows what he’s talking about. The Pioneers are not strangers to post-season play in the spring. They won three state championships in 1997, ’98 and ’99; and even though they haven’t won another one in the last decade since, they’ve always been one of the few teams left standing at the end.And it’s always been Manchester-Essex, it seems, standing with them.”It seems we’re always going toe to toe with Manchester,” he said, “at least, ever since I started coaching. They’ve always had a very competitive program, and so have we.”It just seems to be a natural occurrence every year,” he said. “If it hasn’t been us, it’s been them. Recently, too, Winchester threw its hat in there.”One of his secrets, he says, is that the Pioneers “play a competitive schedule ? each year we try to face different, tougher, competition. Our goal has never been to go through the season unbeaten. It’s to be challenged, individually and to be a better team. And hopefully, we get to a point where we’re at now.”