Gabriel Johnson scored a dramatic winner in second-half stoppage time for the Lions as they completed a league double over table-topping Boro, moving into the play-off places in the process.
The two teams closest to Radcliffe, Hyde United and Warrington Rylands, both remain locked together on 59 points after their respective wins over the weekend.
Lewis Alessandra struck the all-important goal for Hyde just before half-time as they ran out 1-0 winners at Workington, while Warrington Rylands were forced to come from a goal down to pick up all three points away at Bradford Park Avenue.
Mo Touray and James Baillie scored inside the final quarter for the Blues as they ran out 2-1 winners at the Horsfall Community Stadium, with Saturday's result keeping Avenue in the bottom three on goal difference.
Elsewhere, Lancaster City lost ground in the play-off race as first half goals from Curtis Durose and Adam Yates saw the Dolly Blues fall to a 2-1 defeat at Matlock Town.
Worksop Town, another with their eyes on a top-five spot, suffered a similar fate away at Ashton United.
Quickfire goals before the half-hour mark from Alex Byrne and Kellen Adams proved enough for the Robins as they moved up to ninth with a 2-0 win.
Whitby Town's own play-off hopes suffered a setback on home soil, with Ashley Jackson's 93rd minute winner enough to see Gainsborough Trinity climb into the top half thanks to a fifth successive win.
Finally, Atherton Collieries' relegation fears worsened as a Sam Hodgson double helped Morpeth Town come from behind to pick up a 2-1 win at Craik Park.
The Highwaymen have now won back-to-back league games, after a run of five without victory before then.
Results - Saturday 9 March
Ashton United 2-0 Worksop Town
Bradford Park Avenue 1-2 Warrington Rylands
Guiseley 1-0 Radcliffe
Matlock Town 2-1 Lancaster City
Morpeth Town 2-1 Atherton Collieries
Whitby Town 0-1 Gainsborough Trinity
Workington 0-1 Hyde United
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