This article is part of Football FanCast's The Chalkboard series, which provides a tactical insight into teams, players, managers, potential signings and more...

2-0 up and cruising against an anonymous Norwich City side, Southampton looked to be well on course for a straight-forward three points at St Mary's – their second win in at home in the space of a few days.

However, the players were visibly beginning to tire as the hour-mark came and went, and manager Ralph Hasenhuttl clearly noticed as he decided to make his first change of the game in the 72nd minute.

It was Moussa Djenepo that was sacrificed, but rather than a like-for-like substitution it was a defensive midfielder in Oriol Romeu who came onto the field to replace him.

The Austrian manager stuck with the 4-2-2-2 system that has served him so well in recent fixtures at that point, with Romeu sitting deep and James Ward-Prowse moving out to the right flank.

There is no doubt that it took away one of Saints' attacking threats, and while Ward-Prowse is brilliant from set-pieces – as we saw from the two goals – he is far from an attack-minded winger in open play.

Best of the decade: Quickfire Quiz on the last 10 years of Premier League football

Less than a fortnight after Southampton showed that they struggle when the pressure is put on them in the latter stages following Alexandre Laczette's 96th-minute equaliser – they were also let off by Andre Gray's miss against Watford at the weekend – it happened again on Wednesday.

Norwich certainly got some confidence from their 65th minute goal, and were in the ascendency in the last third of the game.

Hasenhuttl followed up his Romeu sub by bringing on Che Adams for Danny Ings, before Maya Yoshida came on for Shane Long five minutes from time.

It was no surprise that the south coast outfit then retreated in the closing stages, and when Cedric Soares slipped in a precarious position the hearts of the St Mary's faithful would certainly have been in their mouths.

Saints survived, just, but Hasenhuttl needs to go back to the drawing board when it comes to his substitutions in future.

He should know by now that his side struggle when they invite pressure onto themselves, and it would have made sense to make attacking changes when bringing the likes of Djenepo and Long off, especially as the Austrian had Sofiane Boufal and Michael Obafemi sitting on the bench.

That is what he needs to do in the future when they have a lead, because these players are clearly more effective when they are on the front foot, and not when their mindset changes to a more defensive one.

The former RB Leipzig manager has been with the south coast outfit for 12 months now, but it appears as though he still has an important lesson to learn if this Saints side are to get some more comfortable wins under their belt.

In other Southampton news, there was no room for Luke Shaw, Dusan Tadic or Graziano Pelle in our Saints Team of the Decade...