With her sleeves rolled up, a baseball cap tugged down firmly on her head and a wide smear of infield dirt across the front of her uniform, Thornton Academy junior shortstop Brooke Cross is the epitome of a tough, gritty ballplayer.

“I love getting dirty,” Cross said. “If it’s not difficult it’s not fun.”

If there’s a tougher player than Cross on the Western Class A champion Thornton softball team, it’s probably her sister, senior Aleisha Cross, who had to scrap for her spot and then her at-bats en route to being named the first-team All-SMAA catcher.

“We like to think we’re pretty tough,” Aleisha Cross said.

With the Cross sisters playing key roles, Thornton Academy proved pretty tough, too.

Touted as preseason contenders, the Golden Trojans stumbled to a 2-3 record, losing one-run games to Bonny Eagle and South Portland, then 5-1 at home by Scarborough on May 5.

Thornton (16-3) hasn’t lost since and Saturday will take its first Western Class A title to St. Joseph’s College to face two-time Eastern champ Skowhegan (15-4) in the 4 p.m. Class A final.

Skowhegan won each of its three playoff games by one run, topping No. 1 Cony 3-2 in the regional final.

After defeating Gorham (11-5) and Cheverus (10-3), Thornton beat Scarborough 2-1 at St. Joseph’s. It was the eighth consecutive trip to the Western Maine final for Scarborough, the state champ in 2007, 2009, 2011 and 2013. Thornton had never made it that far, according to Coach John Provost.

“We thought about how this was their eighth straight trip and they have everything to lose,” Brooke Cross said. “We had nothing to lose. We’ve never been here before and we’re just going to play our game, and that’s exactly what we did.”

Thornton Academy spent Thursday afternoon at The Edge indoor facility in Portland, working on its hitting, which has been a team specialty.

Six regulars hit .400 or better, including Brooke (.420, team-leading 23 runs) and Aleisha Cross (.400).

Erin Brayden, who plays first, led the team with a .640 batting average and 28 RBI. Kaylee Burns (third base) hit .444 with 22 RBI and eight extra-base hits. Center fielder Morgan Dube hit .415 and pitcher Bailey Tremblay batted .416. Dube, Brayden, Burns and Aleisha Cross each hit two home runs.

Aleisha Cross was probably the biggest surprise, Provost said. Early in the season she struggled offensively, prompting Provost to use his designated player to hit for her.

“When I put her back in the order, she came back with a vengeance,” Provost said. “She just finds a way to get her hits. Then she found a way to hit two home runs.”

Brooke Cross had to adjust to her third position in three years on the varsity, having played previously at third base and in the outfield.

“She has tremendous range and her arm strength is amazing,” Provost said. “She’s a gifted athlete.”

Brayden said the Cross sisters are “very competitive” and agreed they have brought an edge to the team this year.

“You can tell the way they play, they always want to win, they always want to compete,” Brayden said. “Brooke, especially, I think intimidates some people out there. I’m not complaining. I’m glad she’s on my team but if I was playing against her, I might have different feelings.”

The Cross sisters credit their parents, Andrea and Gary Cross, who are divorced, for providing first-hand examples of real-life toughness.

“My mom, she raised Brooke and me almost our whole lives by herself,” Aleisha said. “My dad has won awards for heroism, like Purple Hearts, in the military.”

“They’re just both very strong individuals,” Brooke added.

The sisters have played on the same softball team for years, starting with Saco Little League when Brooke turned 9.

This summer they’ll spend time together playing on the Southern Maine Flames travel team but Saturday is the final high school game together. Next year Aleisha will attend Thomas College in Waterville, where she plans to play softball.

“Her senior year, her last year with me, to finish out the last year like this, it’s great,” Brooke said.