McEachern, a senior striker, collected a goal and two assists as Timber Creek advanced to the second round next Friday.
"We worked really hard to make this happen," McEachern said. "It's a big thing for us."
Cherokee (6-6), the No. 12 seed, generated several scoring chances, especially in the first 10 minutes and for much of the second half, but couldn't find the back of the net.
"That's been our story," Cherokee coach Andy Clapperton said. "But you have to give Timber Creek credit. That's a good team. They have a couple girls up top who are really composed with the ball."
Cherokee freshman goalie Devon Kearns, who was making her first varsity start, made seven saves, including a couple of spectacular stops.
"She did a great job," Clapperton said.
Kearns had no chance on Timber Creek's first goal, as Pratt and McEachern worked a give-and-go to perfection.
On the play, Pratt slipped a nice pass to McEachern on the right side. McEachern volleyed a pass right back, and Pratt was alone on the doorstep for an easy goal in the 10th minute.
"Me and Elise work really well together," McEachern said. "I think we're the two best strikers in South Jersey as far as working together."
McEachern scored Timber Creek's second goal in the 35th minute, taking a feed from midfielder Kelly Farrell and blasting a hard shot off the far post and into the net.
"When we're clicking on all cylinders, we're fun to watch," Timber Creek coach Shawn McHugh said.
McEachern and Pratt worked together again for the third goal. This time, McEachern lifted a long cross from the right side to Pratt, who was stationed on the far post.
Pratt tried to head the ball, but it bounced off her knee and into the net.
"She's my favorite," Pratt said of McEachern.
McHugh said winning a coaches tournament game was an important milestone for Timber Creek.
"That's what we talked about in pregame," said McHugh, a first-year coach. "I told them they had a chance to make school history, and they went out and did it."
Cherokee 00–0
Timber Creek 21–3
Goals: TC-Elise Pratt 2, Olivia McEachern.
Saves: TC-Lanye Halliday, 8; C-Devon Kearns, 7.
Contact staff writer Phil Anastasia at 856-779-3223, panastasia@phillynews.com, or @PhilAnastasia on Twitter. Read his blog, "Jersey Side Sports," at www.philly.com/jerseysidesports