'What dreams are made of': Welsh minnows TNS make European history
Holden's header five minutes before half-time put TNS on course to become the first Cymru Premier side to win a group stage match in a major European competition
Declan McManus's 78th penalty clinched the fairytale triumph, which came after TNS were beaten 2-0 by last year's Conference League runners-up Fiorentina in their group stage debut.
Holden hailed TNS's milestone moment as a dream come true for a club that reached the Conference League via a play-off after losing in the qualifying stages of the Champions League and Europa League earlier this season.
"Amazing. What dreams are made of. It's a dream we've had for a long time," he told TNT Sports.
"We've been working our socks off for the last five months and I think it's nothing less than we deserve."
TNS were forced to stage the biggest home game in their history at English League One side Shrewsbury's New Meadow.
UEFA regulations prevented them from playing at their Oswestry home 20 miles away.
But TNS, fresh from a 16-0 Welsh Cup record-equalling victory over Llangollen in their previous match, were right at home nine miles east of the Welsh border.
Craig Harrison's side benefitted from facing Astana's reserves, with the visitors leaving their established players at home to prioritise Sunday's Kazakhstan Premier League clash against Aktobe.
"I had umpteen chances that I would normally take so I was getting to the point where I thought it wouldn't happen. Luckily I know I'm the penalty taker so if we got one I'd get my chance," McManus told TNT Sports.
"We were always going to come under siege a bit. They had a lot of possession and chances for a spell but for the most part we were phenomenal defensively and attacking wise."