Plagued by injury, including fractures to each of his legs, for a couple of seasons, Eisenhut trumpeted his return to top form with a superb display for Roslyn.
On the greasy surface he was an advertisement for the attacking game, leaving opposing players floundering in his wake as he carved through the smallest of gaps.
He put in a lung-bursting shift, from box to box, tackling, passing and, most importantly, ramming in his 36th-minute goal which stunned Technical.
Coach Mike Fridge's Technical had averaged eight goals a game before Saturday, but made no impression on a stalwart Roslyn defence led by general Terry Boylan and first lieutenant Sean Brand.
The Roslyn pair did not miss a tackle.
Boylan also won three headers in attacking set plays within the first 15 minutes, and Brand showed his ability to pass accurately up to 40m to the eager Eisenhut and industrious Ant Hancock.
Technical strung together some stylish passes but Aaron Burgess ploughed a lonely furrow in attack, and his midfield support of Ross Mackenzie, Blair Scoullar, Mike Flaws and Andy Coburn looked dangerous at set plays only.
Roslyn's one-goal lead looked fragile when referee Jeff Clamp red-carded Liam Dunbar just before half-time, but coach Boylan organised the second half to frustrate Technical, and his team responded brilliantly.
"We knew we could win," Boylan said.
"It was a matter of belief. I stressed that, and the Roslyn players, spurred on by the best support in town, showed they had the guts to deliver a superb result."
"Fridge was blunt in assessing hid side, saying: "We played poorly and paid the penalty."
Despite Grants Braes scoring first, Caversham went on to win 6-1 at Ocean Grove, and with Technical and Roslyn on 15 points, Caversham is back in the hunt close behind on 13 points.
Green Island remains fourth on 12 points, despite losing 2-3 at home to Queenstown, which has climbed into the top six on its recent run of winning form.
Since new coach Jamie Whitmarsh took over, Queenstown has won its last three games and scored nine goals.
Coach Kenny Cresswell's Southland FC confirmed its mid-table place with a convincing 5-1 win over the struggling University side.
Barry Gardiner scored twice, and Wade Griffin, Fabian Wanjura, George Hercus chipped in, with Mark Nagel getting Varsity's consolation.
At the Caledonian ground, Northern beat the Otago Youth side 4-0 on a day the Youth defence will want to forget.
However, the first Northern goal was a ripper by Simon Collins that gave keeper Tom Galloway little chance.
Northern forged further ahead when Tom Smith, Jason Anson and Jason Burgess scored.
The Youth team also created some good attacking moves and Michael Still went close a couple of times, but defensive frailty was the Milk Cup side's downfall.
Mosgiel had the bye.
