Joint manager Jason Lee felt Boston United's display at Bishops Stortford in Blue Square Bet North was poor despite a 1-0 win for the Pilgrims.
Marc Newsham scored in the sixth minute of added time after a Ben Milnes free-kick to snatch the victory for Boston against the 10-man hosts.
"I'm delighted with three points, we didn't think it would come," Lee told BBC Lincolnshire. "We didn't play well.
"The performance was disappointing but the three points could be invaluable."
Goalkeeper Paul Bastock produced several good saves to keep Bishops Stortford at bay, even after they had defender Phil Anderson sent off on 71 minutes following an altercation with Ryan Semple.
"When they go down to 10 men everyone expects you to go on and turn in a decent performance," added Lee. "But they kept the ball well, certainly better than us, and we rushed things and our quality was poor.
" As much as I like us to play nice football we should have overpowered them.
"But if we're going to be challenging to get out of this league we need to be better, our quality needs to be better and we need to create more chances."