Two extra time goals by Rugby Town finally ended the dogged resistance of lower level Harrowby at Butlin Road.
Despite having been on top for large parts of the Vase tie, Rugby were unable to find a way past the Grantham-based opposition in the initial ninety minutes.
However a Fabian Smith penalty broke the deadlock near the end of the first period of extra time, before Tevin Shakespeare then confirmed Valley’s place in the next round.
Brad Harris replaced the suspended James Dance in Town’s defence, with Harry Holloway and Jamie Hall also back in the starting line-up in three changes from the previous weekend’s home league defeat to Wulfrunians.
The visitors almost took the lead within the first minute of play though, when Sam Grouse got in behind the Rugby back-line – only to lift his effort over the bar.
Thereafter the bulk of the attacking intent came from Town, and ex-Valley keeper Sam Andrew was soon blocking a goalbound strike by Trey Brathwaite with his legs.
Josh Ruff sent a couple of free-kicks off-target from just outside the box and Andrew did particularly well to keep out a downward header by Ruben Wiggins-Thomas to Aiden Print’s cross.
With the swirling wind having an adverse effect on the first half as a spectacle, United’s only other chance saw Niall Cooper palming away a swinging Jurelle Phillip’s free-kick.
Harrowby made an even quicker assault on the Town goal at the start of the second period, with Cooper off his line quickly to deny Twanda Bilson’s surge from the kick-off.
However it was pretty much one way traffic from then on, with Andrew putting in a fine display against his old club and Rugby again struggling to convert their dominance into goals.
Wiggins-Thomas’s cross was cut-out with strike partner David Kolodynski ready to pounce, whilst Sean Castleton headed Ruff’s corner over and Jamie Hall had a further headed chance blocked on the line.
When Holloway was taken out in the box by Felix Hogg in the 70th minute, it gave Wiggins-Thomas the opportunity to score from the spot for a second weekend running, but the striker’s penalty lacked both power and precision – and Andrew was able to push it away and also prevent the taker from converting the rebound.
Substitute Shakespeare then hit the post after Brathwaite’s deep free-kick fell to him, with Shakespeare having a further shot blocked in the box by a Harrowby body – a fate which subsequently also befell strikes from Castleton and Print.
Andrew pulled out two further top drawer saves in the closing minutes of normal time, with Smith’s powerful effort parried and Wiggins-Thomas’s connection to Print’s cross also kept out.
Therefore the game went to extra-time, with Chadd Birch and Smith both having early chances to make a breakthrough.
A stooping header by Jack Whyley which was comfortably taken by Cooper represented a rare moment of anxiety for home supporters, before Town were then awarded their second penalty of the game when Joe Briers clipped Brathwaite.
Smith took over the spot-kick responsibilities and stroked the ball into the left corner of the net to give Valley the lead.
The game was sealed with nine minutes remaining when Shakespeare finished off Birch’s cross at the far post.
Line-up: Cooper; Kelly, Harris, Castleton; Print, Hall (Birch), Brathwaite, Holloway (Smith), Ruff; Wiggins-Thomas, Kolodynski (Shakespeare). Subs not used: Thornton, Miveld. Booked: Brathwaite.
Harrowby line-up: Andrew, Bilson, Phillip, Havron, Whyley, Currall, Briers, Carta, John, Grouse, Hogg. Subs: Sylla, McCartney, Parker-Lax, Milne, Smith.