The Blades are through to the fourth round of the FA Youth Cup, after another thrilling penalty shootout success in Lancashire.
Having beaten Oldham Athletic on spot-kicks at Boundary Park in the first round, before comfortably disposing of Worcester City at Bramall Lane in round two, United were victorious at the Reebok Stadium on Friday night, after a late goal had cruelly denied them a win in normal time.
United, in yellow and green, almost suffered a disastrous start, when Thomas and Newby combined for the hosts, but thankfully a powerful shot from the latter went inches wide. Moments later Eastwood collected Bailey's shot at the second attempt.
At the other end United responded immediately, only for William Jaaskelainen to produce a fine save to deny Calvert-Lewin from close-range.
The game ebbed and flowed with chances at a premium, until the Blades took the lead in the 34th minute. Good work by the industrious Coustrain played in KHAN, who calmly slotted the ball past the advancing Jaaskelainen.
Bolton responded by finishing the first-half strongly, but Bailey's long-range didn't trouble Eastwood.
The first action of the second-half saw Eastwood spill Thomas's free-kick, but the young goalkeeper recovered to deny the onrushing Torres. Eyre responded for the Blades, stinging the palms of Jaaskelainen.
Coustrain a constant threat to the home side came within a whisker of doubling the lead, but his chip, which left Jaaskelainen stranded, clipped the top of the crossbar and went out of play. The woodwork rescued the Trotters again in United's next attack as Dimaio smashed a shot against the goal frame.
After Newby had just failed to connect with a Thomas free-kick, Khan became the third Blade to be denied by a coat of paint as his free-kick cannoned off the post before being cleared to safety.
A point blank save from Jaaskelainen denied Khan, before Eastwood was alert to Cvetko's shot with Abbott ready to pounce on the rebound.
Just when United thought they had seen the game out, ABBOTT rifled home a stunning long-range effort, with virtually the last kick of the game to send the clash into extra-time.
The first period of extra-time was a cagey affair, with neither goalkeeper called into any meaningful action. Unsurprisingly, the second period also failed to see either side snatch a winner meaning penalties would decide who travelled to Bradford City or Millwall in round four.
Bolton went first in the shootout and both teams scored three penalties apiece before misses from Torres and Holding (Eastwood making the save), either side of Paling converting, settled the tie in United's favour.
Dimaio, Calvert-Lewin and Khan were the Blades other scorers in the shootout.
Blades: Eastwood, Paling, Ptak, Dimaio, Evans, Banton, Calvert-Lewin, Whiteman (Ishmail 89), Eyre (Cockerline 64), Khan, Coustrain (Reed 73).
Unused: Cheeseman, Owen.
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