Both Castro and Tubb put unassisted goals into the Pioneer net, as they helped the Scots overcome an early goal by Transy.
The victory gives Maryville its second-straight victory after its 8-0 USA South win on Thursday.
Transylvania University would score first, just 1:53 into the match. A Maryville foul at the top-right corner of the box would give the Pioneers a free kick. The kick was a cross to the middle, as Cecilia Walton headed the ball to the back right corner of the box. Morgan Janes collected the ball, putting it into the net from just 10 yards out for a 1-0 lead.
Maryville would fight back, however, as Castro would tally her first goal of the season in the 30th minute. The ball popped in the air in the box, as Castro brought it down. She put it in the corner for a 1-1 score.
The match would go scoreless, though, until late in the second half. Tubb would add the game-winner in the 74th minute with her second goal of 2017. Tubb would take a cross ball with a half volley, pushing it toward the net. It would deflect off the keeper and into the corner. With 73:05 on the clock, the Scots held the lead, 2-1, which they would ride to the victory.
Maryville Rachel Taylor moves to 3-2-1 in net, as she recorded a pair of saves with 90 minutes in goal.
Transylvania (2-3-1) saw Janes lead the way with three shots, two of those on goal. She scored the Pioneers only goal, as Walton earned the assist.
Ally Barfield falls to 1-2 for Transy, as she recorded seven saves in net. She gave up a pair of goals in 90 minutes.
Maryville will look next to a pair of home contests on Saturday and Sunday, Sept. 23-24. The Scots will take on Wesleyan College (Ga.) on Saturday at 2 p.m., before hosting the Panthers of Ferrum College in a 1 p.m. start on Sunday.