Tim Sills, on loan from Stevenage Borough netted the only goal of the game at Nene Park in their Blue Square Premier League fixture.
Aksalu, an Estonian international joined the Field Mill club on loan from the Blades last week and will remain with David Holdsworth's Stags for two months.
It is hoped that whilst at Field Mill the shot stopper will gain necessary experience and could one day be used as a united number one.
Manager David Holdsworth told mansfieldtown.net: "It was a real blow to lose Alan Marriott but I have had to move quickly to seek a replacement. I am delighted to sign an experienced goalkeeper like Mihkel. He will now play a big part in our season over the next few months which will prove fundamental to our campaign."