Connor Brown had a debut to forget for the Lions when he diverted a Kevin Amankwaah cross into his own goal.
The U's built early pressure with Chris Dickson, Roarie Deacon and Dan Wishart wasting good opportunities to open the scoring before Brown's own goal gave them the lead just before the break.
Bottom club Guiseley almost equalised when Jordan Preston had a 30-yard effort denied by a wonderful save from Ross Worner before Preston and substitute Michael Rankine had golden chances to level from close range late on but could not convert.
Report supplied by the Press Association.
Match ends, Sutton United 1, Guiseley 0.
Second Half ends, Sutton United 1, Guiseley 0.
Substitution, Sutton United. Daniel Spence replaces Chris Dickson.
Simon Downer (Sutton United) is shown the yellow card.
Substitution, Guiseley. Michael Rankine replaces Reece Webb-Foster.
Substitution, Guiseley. Nicky Clee replaces Simon Walton.
Substitution, Sutton United. Maxime Biamou replaces Dan Fitchett.
Second Half begins Sutton United 1, Guiseley 0.
First Half ends, Sutton United 1, Guiseley 0.
Simon Walton (Guiseley) is shown the yellow card.
Own Goal by Connor Brown, Guiseley.  Sutton United 1, Guiseley 0.
Jordan Preston (Guiseley) is shown the yellow card.
Reece Webb-Foster (Guiseley) is shown the yellow card.
First Half begins.
Lineups are announced and players are warming up.
Guiseley remain winless in the National League after they fell to a defeat at Sutton.