Weymouth 0 Torquay United 3 - An emphatic win for the Gulls
Sills was ruled as very doubtful by boss Paul Buckle after picking up a knock in Saturday's 2-0 win over Mansfield, but came through training and spearheaded the Gulls' charge into the fourth round of the competition.
It was a superb all-round performance from the visitors, who rarely gave Weymouth - conquerors of Kettering just three days earlier - a glimpse of goal.
In fact, the home side only had one effort on target...and that was in the second minute.
After Sills' early double, it was his replacement Elliot Benyon who rounded things off with 12 minutes to go.
It couldn't have been much more comfortable...just a shame that only 621 braved the chilly Dorset night to see it.
Gulls boss Buckle resisted the temptation to tinker with his side, and named the same starting eleven which beat Mansfield Town 2-0 at Plainmoor on Saturday.
Sills was the surprise inclusion, and that meant no substitute spot for trainee Jordan Charran - instead the returning Matt Green was given a seat on the bench.
Terras counterpart John Hollins, meanwhile, made six changes from the side who shocked Kettering at the weekend - the major absentees being joint top-scorers Chris McPhee and Michael Malcolm.
Former Gull McPhee was dropped to the bench, while fellow six-goal man Malcolm was completing a loan move to Crawley.
With Sills in the side, the Gulls were always going to be an aerial threat in the home penalty area - and so it proved after just three minutes.
A Kevin Nicholson short corner was whipped in delightfully from the left by Mustapha Carayol, and Sills rose unchallenged to glance a header past helpless Weymouth goalkeeper Richard Barnard.
Any illusions United had of a walk in the park were quickly dashed though - recalled striker Pierre Doubois had nipped in behind Steve Woods and forced Scott Bevan into a good low save just seconds before the opening goal at the other end.
And a few moments after, home skipper Kevin Sandwith let rip with a ferocious 25-yard volley that whistled inches past Bevan's left upright.
But with 16 minutes on the clock, Sills capitalised on yet more luxurious space in the Terras' final third to double the lead.
Nicky Wroe broke down the right with Weymouth appealing for a handball, and dinked a ball in for Sills to control on his chest, before turning and scooping an effort over Barnard from the edge of the box.
The rest of the first-half petered out after Sills' second, with the Gulls knocking the ball around fairly comfortably and controlling the tempo at their leisure.
Home full-back Cameron Mower almost gave them a wake-up call when he charged into the box in the 39th minute, but Lee Mansell was alert to the danger and came across to cover with an excellent block.
Such precise timing wasn't so evident from Weymouth centre-half Adam Bygrave in the opening moments of the second-half - he was yellow-carded for a foul on Roscoe Dsane, but Nicholson fired an ambitious 30-yard free-kick low and just wide.
Torquay clearly weren't going to rest on their laurels though, and the industrious Wroe slipped a cracking cross-field ball for Tyrone Thompson to blast just wide.
Seconds later, Thompson got his head to a Nicholson corner but planted it right into Barnard's chest as the visitors stepped up their bid to put the tie to bed.
Wroe and skipper Chris Hargreaves were pulling all the strings in midfield, and Carayol - who swapped wings with Dsane for the second-half - was really starting to enjoy himself down the right flank.
In fact, he was only inches from adding a 71st minute third when he showed some dazzling footwork to bamboozle ex-Gull Stephen Reed before curling an effort just wide.
Home boss Hollins tried to give his side an extra attacking edge by replacing Sandwith with McPhee, but it didn't appear to bother the visitors.
And soon it was 3-0, largely due to the brilliance of Carayol and another cracking delivery.
Wroe roamed forward before poking the ball out to the right, and the former MK Dons man whipped in another majestic ball for substitute Elliot Benyon to head home.
Benyon had been sent on for Sills at the start of the second-half and, once that third goal had gone in with 12 minutes remaining, Gulls boss Buckle took the opportunity to send on Green and Danny Stevens.
Green came on for Thompson, and Carayol was replaced by Stevens, who almost gave the scoreline some added gloss within two minutes of his introduction.
After linking up well with Hargreaves, he cut the ball back in the box for Wroe to unleash a low drive that beat Barnard but went the wrong side of the post.
Green didn't get much chance to see the ball in the final 10 minutes as the visitors started to ease their foot off the gas.
A free-kick 30 yards out in the final minute of injury-time gave them one final sniff of a fourth, but Wroe thumped his shot against the Weymouth wall.
