A 4-1 win at Elland Road saw Leeds finish their seven-match summer schedule without defeat and provided ideal build-up to next Saturday's opening League One match at Scunthorpe United.
United created countless chances in the first half and established a 3-0 lead at half-time through goals from Paul Huntington, Rui Marques and Jermaine Beckford.
Huntington broke the deadlock in the 24th minute when he drove home a low shot from 10 yards out, and Marques doubled United's lead four minutes later with a header from Robert Snodgrass' corner.
Beckford added a third when he skipped past Dender goalkeeper Alexandre Martinovic and clipped a controlled finish into the net, and Dender's sole chance in the first period came on 44 minutes when Norman Sylla guided a lob beyond an empty next after a mix-up between Casper Ankergren and Frazer Richardson.
Dender pulled a goal back on 56 minutes when Bart Van den Eede converted the rebound from Sylla's blocked shot, and Sylla missed another great chance on the hour when he hooked the ball over the bar with only Ankergren to beat, but Leeds wrapped up their win four minutes from time when Huntington headed home Peter Sweeney's corner.