As Allan Saint-Maximin's number flashed up on the board and Paul Dummett stood on the touchline waiting to replace the Frenchman - it did it long for some to criticise the decision.
'Cosmic', 'what?' or 'TV off' were just some of the replies on social media - but in hindsight, it was a masterstroke from Steve Bruce.
With his side down to ten men - Jeff Hendrick sent off for two yellow cards - Newcastle had gone 17 minutes without any chance other than to sit deeper.
In that time Southampton had four shots on goal - including Danny Ings effort which struck the post and bounced back into the arms of Karl Darlow. The Saints were on the ascendence and Newcastle were looking likely to cave as the visitors made 142 passes with 58 of them in United's final third.
The pressure was mounting and United's final change - after replacing Callum Wilson and Javier Manquillo - was always likely to be a defensive one.
Many looked upon Saint-Maximin as the outlet for Newcastle in this situation, the one who would break away and carry the ball downfield to break up the play. It's not a bad theory but given he was starting his first game since November, had already assisted twice and made the most dribbles (7) - he was understandably looking a bit leggy.
Dummett, who in the match-day programme had spoken about being described as 'Ronseal - because it does what it says on the tin' - came on and did ever so well.
It was perhaps a surprise given that Bruce had told reporters on Friday that Dummett was struggling, maybe even more of an idea of the defensive troubles Newcastle have got that the left-back was called upon.
Those defensive worries have only increased with Fabian Schar stretched off with 13 minutes left. By that point, Newcastle had used all their subs, and Dummett alongside Isaac Hayden found themselves really up against it - but they coped.
Dummett - tied with Emil Krafth - made the most clearances of everybody (7) and won three of his four aerial duels, whilst Hayden, a makeshift defender, put in another top performance at the back - making six clearances and one interception.
Hindsight is a wonderful thing, but bringing Dummett for the 20 minutes of need really was a key element to victory over Southampton.
