Midfielder Teemu Tainio came in in for Didier Zokora, who was on the bench alongside Jermain Defoe, who made the 16 after recovering from a foot injury sustained at Bolton.
THE KEY ACTION...
5mins: CLOSE. Tainio played it wide to Keane who stepped inside Bromby and hit early cross for Berbatov who was inches away sliding in six yards out.
7mins: GOAL - SPURS. Brilliant pass from Keane released Lennon down the right, he turned Armstrong inside out before crossing low for Berbatov to tap home from six yards.
Spurs 1, Sheffield United 0
10mins: Deep cross from Keane picked out Berbatov, he headed down for Tainio to strike over from 18 yards, difficult chance though.
12mins: Great angles from Keane dropping deeper, pass almost picked out Berbatov's run in box, only slightly overhit.
15mins: Tonge thunderbolt from distance might have been interesting but Davenport managed to block with his head.
17mins: GOAL - SPURS. Great team goal. Keane floated pass from just inside Sheffield's half that Berbatov climbed high to nod into path of supporting Jenas, he took header in his stride, controlled and finished in style.
Spurs 2, Sheffield United 0
18mins: Webber cut in from left, decent strike from left edge of the box but routine save for Robinson.
19mins: Keane again, this time threaded pass through to Tainio charging into box, Sommeil did well to clear for corner. From corner, Keane inswinger headed just wide by Berbatov.
22mins: Keane and Lennon pulling strings 30 yards out, exchanged passes then Keane clipped pass into Lennon right side of box, he worked a yard against Armstrong and looked to pick out Berbatov again, this time Kenny able to cut out.
28mins: SAVE. Davenport exchanged passes in break from defence, ball eventually went in to Tainio and then Keane scuffed shot that fell to Berbatov, 18 yards out, snapshot heading inside left post before Kenny palmed away.
37mins: Davids did well centrally and found Lee, he released Lennon down the right, typical pace and whipped in cross that was just behind Berbatov.
Added time: Great block tackle from Davenport as Jagielka found space in dangerous area, centrally, 25 yards out.
Half-time: Spurs 2, Sheffield United 0
55mins: CHANCE. Kept possession for ages, eventually Lee played in Berbatov down the right, he held play up and picked up Lee again on the edge of the area, blasted over from 16 yards.
59mins: Heart in mouths as Sommeil went down in heap trying to get onto Gillespie's pass, nothing awarded.
60mins: SUBS - SHEFFIELD UNITED. Montgomerie and Nade for Unsworth and Sommeil.
62mins: MISS. Lee's quick throw released Lennon, into boxm cut ball back for Keane who miss hit shot eight yards out.
63mins: YELLOW CARD. Bromby for foul on Tainio.
66mins: Lennon flying down right side, 50-yard run, passed wide to Jenas who overhit cross looking for Berbatov.
67mins: Two great blocks, Dawson to deny Akinbiyi and then Davenport threw himself in front of Nade's effort.
68mins: Tonge worked short corner with Gillespie, chance to shoot, dragged wide from 20 yards.
69mins: SUB - SPURS. Zokora for Tainio.
71mins: Keane laid ball back for Jenas to let fly, Montgomerie there to make block.
72mins: Davids run and shot blocked by Morgan.
72mins: Space opened up in front of Assou-Ekotto, carried for about 10 yards before shooting from 25 yards out, deflected off Jagielka for corner.
74mins: CHANCE. Sheffield's best move, Montgomerie to Nade, low ball across the face of goal that Akinbiyi agonisingly inches away from sliding in.
79mins: CLOSE. More brilliant wing play from Lennon, this time on left, nutmegged Bromby, hit the byline, low cross would have been slotted home by Keane but Jagielka slid in to intercept.
79mins: SUB - SHEFFIELD UNITED. Quinn for Gillespie.
80mins: CHANCE. Jenas in box, laid back for Keane, unmarked centrally 18 yards out, didn't get hold of shot straight at Kenny.
81mins: SUB. Defoe for Keane.
82mins: Tonge half-volley ended up in higher reaches of Paxton Road.
84mins: SAVE. Great possession, probing away, eventually Jenas into Defoe, he left Jagielka in a heap before attempting curler from 18 yards that Kenny did well to turn away.
85mins: Dawson 20-yard header straight at Kenny.
86mins: SAVE. Lennon won possession back off United centrally, into Defoe, he smashed it from 30 yards and Kenny showed good reactions to palm away.
86mins: Lee tried his luck from 30 yards, sliced well wide.
89mins: Quinn curled 25-yard free-kick just wide, Robinson always had covered.
Added time: SAVE. Defoe laid ball back for Davids to strike from 25 yards, clean hit tipped over by Kenny.
Full-time: Spurs 2, Sheffield United 0
Spurs: Robinson, Lee, Assou-Ekotto, Dawson, Davenport, Lennon, Jenas, Tainio (Zokora, 69), Davids, Berbatov, Keane (Defoe, 81). Subs: Cerny, Stalteri, Gardner.
Sheffield United: Kenny, Bromby, Unsworth (Montgomerie, 60), Morgan, Jagielka, Akinbiyi, Webber, Sommeil (Nade, 60), Tonge, Gillespie (Quinn, 79), Armstrong. Subs: Kozluk, Leigertwood.
Referee: Mr P Walton. Assistants: Mr D Richards, Mr M Yerby. Fourth official: Mr P Armstrong.
All the action from tonight's 2-0 Premiership victory against Sheffield United at the Lane.