The Easter Road boss was outspoken in his criticisms on Monday as he lambasted his players following a home defeat to St Johnstone. But he was overjoyed that his players had taken his words on board to put on a far more disciplined display against St Mirren, winning in Paisley through Leigh Griffiths' 72nd-minute penalty.
Fenlon - whose side move up to fourth in the Clydesdale Bank Premier League - told Press Association Sport: "It's good to be back winning. That's the important thing. Now we've got to make sure we kick on.
"If you look at the two performances, we knew on Monday night that the St Johnstone game wasn't us, we were poor. We spoke about it during the week and what we worked on has paid off. I'm delighted with the lads.
"It's a massive three points for us with the league being so tight and that's what makes Monday so disappointing. If you can win your home games then come on the road and pick up something, it can make a massive difference to the table.
"We were a lot better. Our shape was excellent from start to finish, I thought we passed the ball really well, particularly in the first half, and when we lost the ball we got a lot of numbers back and made it difficult for St Mirren to break us down."
Griffiths was handed his spot-kick opportunity after St Mirren skipper Jim Goodwin was penalised by referee Willie Collum for an alleged barge on visiting winger Matt Done, who theatrically threw himself to the floor at the first hint of contact.
Boss Danny Lennon, though, refused to vent his true feelings until he had had a chance to review the incident.
"I didn't see it at the time, the fourth official was standing in my way," he claimed. "But when I saw the ball come in I didn't think there was any apparent danger.
"We seem to be getting conflicting stories from the officials. Until I see it again, that's as much as I'll say on it."