Spalding United remain top of the Midland Division of the Northern Premier League, despite surrendering their unbeaten record to Loughborough Dynamo on Saturday.
A 3-1 defeat saw all the goals come in the second half and, while manager Elliot Sandy insisted there as no need to panic, he was determined to make sure lessons were learned.
“I was so disappointed and it just felt like we turned up and thought we’d win,” he said.
“Since I’ve been manager, it’s the worst 90 minutes that I’ve seen from any of my teams and it’s nowhere near good enough.
“Fair play and credit to Loughborough. They played well and took their chances but we just weren’t at it at all.
“We looked lethargic, going through the motions, which is definitely something that will be addressed.
“We’re still top of the league, it’s our first loss, so we don’t need to panic but we definitely have to improve – whether that’s having to get players in or working harder in training.
“We know what we need to do as a club and I know what I need to do as a manager. I’m not going to accept that again.”
A low-key first half was devoid of clear chances for either side but, after the break, the hosts took the lead through Evan Garnett when they capitalised on some poor defending.
A goalline clearance denied Jordan Graham a swift equaliser but Sam Warburton celebrated an early present when he drilled in a low shot to make it 1-1, three days ahead of his 27th birthday.
However, Loughborough wrapped up all three points with two goals in the last 11 minutes from Rio Molyneux and Garnett.
James Snedden made his Tulips debut, following his arrival from Shepshed Dynamo, but was unable to inspire his new teammates to victory.
Spalding have the chance to re-establish their superiority at the top of the table with two games in four days, welcoming Boldmere St Michaels on Saturday before a trip to Gresley Rovers on Tuesday.
Tulips: Breeden, Draper, Warburton, Snedden, Stainfield, Cartwright, Carvalho, Clifton, Graham, Hilliard, Walker. Subs: Sandy, Winters, Curtis, Morley.
Attendance: 148.