The Canberra Cavalry were charging towards a cleansweep of Geelong-Korea and a chance of top spot in the ABL north-east conference.
But they gave up a two-run lead and then a Steve Kent brain explosion saw them drop the fourth-and-final game of the series.
Korea scored three runs in the final two innings to win 4-3 at Geelong on Sunday.
Scores were tied in the bottom of the ninth, when Kent walked lead-off hitter Seung-Hyun Baek.
Well, the umpire thought it was a walk. Kent disagreed.
He was unhappy with a couple of the calls and vented his frustration at the official - who swiftly ejected him.
Cavalry manager Keith Ward was also ejected as he tried to buy some time for pitcher James Mulry to warm up.
Korea outfielder Woo-Hyun Song drove in the winning run with a walk-off double.
"Obviously [Kent] was pretty emotional because it was the bottom of the ninth, a tied ball game, your closer's in there and making pitches and not getting them," Ward said.
"It's pretty frustrating. Stevie runs pretty hot at the best of times and obviously when he's not getting calls that he thinks are strikes [even more so].
"It's actually nice to see some emotion and fire from the guys.
"Even though we'd already won three games in the series the boys were obviously hungry and desperate to get over the line."
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It overshadowed a big weekend for the Cavalry as they climbed into second spot in the north-east behind Auckland Tuatara.
Before Sunday they'd beaten Geelong by a combined score of 24-7 to win the three opening games - and making it seven wins from their past nine games.
Cavalry starter Frank Gailey made a successful return to the pitching mound, giving up four hits and one run in four innings, while striking out three and walking two.
The run he gave up came in the second, when Byeong-Woo Jeon hit a single to centre field to open the scoring.
Cavalry first-base Zach Wilson hit a two-run homer, before Kyle Perkins' solo shot had Canberra looking comfortable.
That was Perkins' 23rd home run of his career - and his third across the series - giving him the Cavalry's all-time record ahead of Jack Murphy.
Wilson moved to outright fifth with 18 - in just his second season.
Scores were levelled when Jae-Won Lee drove in a run in the bottom of the 8th and then a Singo Hirata wild pitch brought another runner home.
"I'm really happy for him because Kyle's career and the record are probably a reflection of his perseverance and the fact you have to adapt to survive in professional sport," Ward said.
"He's gone from a catcher to a pitcher back to a catcher, and now probably he's a little bit of a utility.
"It's been a long road for him and we've always had a lot of confidence in his ability.
"Early on in his career he probably didn't quite believe in himself enough. The guy's a soldier and he's a good teammate."
The Cavalry host the Adelaide Giants at Narrabundah Ballpark for the first time since they changed their name from the Bite, with the four-game series beginning Thursday.
AT A GLANCE
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GEELONG 010 000 021 4R 8H 0E