Walker put up 6 runs in the top of the second, 2 in the third and 7 in the sixth inning while Excel responded with a deuce in the fifth inning and one run in the sixth, closing to 8-3.
The Eagles (2-14, 0-13 in Region 6-A) also advanced a runner to third in the sixth only to strand him before completing their run at the scoreboard.
Head coach Michael Adcock said Excel got a good pitching effort from Zach DaCamara and Alex Willingham but the defensive play behind them did not take advantage of their opportunities to stymie their run-scoring.
"We got great pitching tonight," Adcock said. "Alex did a great job of keeping them off balance. Two or three times with runners at first and second and one out, he made a great pitch and induced a double-play ball but we didn't complete it.
"I think three times we also got a ground ball with the bases loaded and could have made a play at home but we didn't get an out anywhere. That's kind of been our Achilles' Heel all year, making defensive miscues at the most crucial times."
Adcock said the Eagle offense also needs to be more opportunistic.
"We seem to lack the ability to get that big hit, likewise, at a crucial point in the game. With runners in scoring position with two outs or less, we seem to not be able to find the rhythm of executing it and get that crucial momentum going."
Phillip Looney scored Excel's initial run in the fourth inning after getting on with a single. He went to second after a single by Alex Berrey, advanced to third on a sacrifice by Mason Butt and scored when daCamara hit a 2-RBI single that also advanced Berrey across home plate.
The Eagles closed out their scoring in the fifth after John Hood singled his way on and took second after Lane Blackwell drew a base on balls. Looney then hit an RBI-double to send him home.
Adcock said the Eagles tried to claw their way back into the contest in the fourth and fifth innings but came up short. "We fought back and brought it within 5 runs, 8-3, and were sitting there with runners at second and third with two outs, and we just couldn't push those two runs across."
He said learning to score in those situations is a key to the development of the Eagles.
"You get a hit in that situation and you make it an 8-5 ball game, a 3-run game," he said. "We try to explain to our kids that a 3-run ball game is a lot tougher on a pitcher with runners in scoring position than a game where they have an 8-to-nothing lead and nobody on base. It changes the whole outlook and strategy of a game and what both teams are trying to do. It creates more pressure on the defense. Unfortunately we're not getting the timely execution."
The coach said while Excel has some growing to do, he's not taking anything away from Walker's play.
"They're a very good ball club. Mike Brady does a great job of coaching those guys and they're fundamentally sound," he said. "They got a heck of an effort from their pitcher today. He's a Division 1 prospect. He's got good velocity, in the upper 80s or low 90s, and he's great with off-speed and hits the spots well. It was a great effort on their part. They're just a great, all-around, well-coached ball club."
The loss improved Walker's record to 12-7, 8-4.
Excel returns to the diamond Monday when it plays North Cobb Christian. The game is scheduled to start at 4:30 p.m.