It was only the Reds’ second win at the New Buck’s Headand ended a run of four defeats.
Craig Westcarr and Tom Allan scored in the first half before before Telford pulled a goal back through Elliot Newby before the break.
“it was probably our best performance to date — not about playing but organisation and the willingness to put a shift in,” said McDermott.
“People dropped into the right areas, filled the gaps and the effort was non-stop for 97 minutes.
“Tom Allan, Luke Shiels and Billy Priestley were good, but Tom was like a magnet to the ball.
“When you needed someone to go and head it, he did it in both boxes and was outstanding.
“l don’t like to pick individuals out because it was a massive team performance — everyone brought to the table what they’re good at.
“Dizz [Craig Disley] was like a proper captain — he ran around, he got around the pitch and he led the team .
“Bradley Wood was on a different level, he was amazing.
“Brendon [Daniels] in the hole — it’s a luxury little position, but we said to him he has to work hard and he hasn’t scored goals with massive free-kicks and stuff, but he’s looked a complete player.
“The way he wanted to work for the team — if he can do that for us the rest of the lads will follow him.
“l’m delighted as it’s a bit of pressure off us. We’ve stopped the rot.”
Westcarr gave Alfreton a 27th-minute lead with a deft chip over keeper Jasbir Singh after Disley had poked the ball through to him 12 yards out.
Five minutes later the advantage was doubled when Allan leapt to head home a deep Daniels free-kick at the back post.
Newby reduced the arrears for the home side in the 44th minute when he drilled the ball low from the edge of the area after a right wing cross had not been cleared.
The Reds soaked up pressure in the second period and it needed a last-ditch goalline clearance by Wood to deny Max Leonard.
Keeper Chris Elliott also made a decisive double save from Marcus Dinanga during an seven minutes of added time.
At the other end Alfreton’s clearest chance of the second half saw Westcarr foiled by a block from Connor Johnson 12 minutes from time.
TELFORD: Singh, Simpson [Dwyer 71], Wilson, C. Johnson, Sutton, Cowans. Leonard, Lussey, Dinanga, Barnes-Homer [Murphy 71], Newby. Subs not used: Hayden, Martinez, McGrory.
ALFRETON: Elliott, Topliss [Marshall h/t], Shiels, Allan, Priestley [Everington 83], Keane, Wood, Disley, Daniels, Westcarr, Shariff [Robertson 63]. Subs not used: A. Johnson, Weatherer.
Referee: Aaron Jackson.