Andy Peaks was left frustrated after AFC Rushden & Diamonds fell at the first hurdle in the Southern League Challenge Cup.
The Diamonds boss picked a strong team to take on lower-ranked Kempston Rovers but they found themselves 2-0 down at half-time.
They stormed back in the second half, however, as goals from Declan Rogers and Jack Bowen put them on level terms.
Neither side could find a winner in 90 minutes, meaning it went to a penalty shoot-out and Diamonds mis-fired from 12 yards as Ben Farrell, Liam Dolman and Zack Reynolds all missed from the spot with Kempston winning it 3-1 to advance.
But Peaks was left heartened by his team’s overall display, although he admitted some “terrible errors” proved costly.
“It was very frustrating overall,” the Diamonds boss said.
“I picked a strong team because I really want us to get some momentum and we actually played quite well in the first half.
“But we made some terrible errors that cost us massively. Our defending was poor at times and Kempston punished us for it.
“I had to make some changes at half-time and I was really pleased with our second-half performance.
“We scored the two goals and we could have easily gone on to win it. It took some great defending from them to keep us out and fair play to them for that.
“We deserved to win the game before penalties.
“Unfortunately, we weren’t very good in the shoot-out and I can’t really legislate for that.”