Sports psychology has become an ever more important factor in top level football in recent years as the search for those marginal gains towards success grow ever more focussed.

The old fashion method of putting an arm round the shoulder of some players and giving others a rollicking was about as complex as it got.

Nowadays, with the nuances of managing multi-millionaires, drawn together from a disparate range of countries – as well as the managers themselves - and performing at such a high level, it is slightly different.

However, it is still ultimately the manager who has to crack the formula for success, for getting the best out of each individual, but also having that knack of knowing which players will gel together to form a cohesive squad and team.

It’s something the best managers have always had instinctively.

Claude Puel is now having to deal with issues of mind rather than body with his players, and he knows that if he doesn’t get it right soon that the end to this season is going to fall very flat indeed.

The Saints manager admitted after the 3-0 defeat to Manchester City that his players seemed nervous.

On first glance it seems baffling. Saints came into the game on the back of seven points from three games, and with their star striker, Manolo Gabbiadini, back from injury.

You would have thought their confidence would be high and with nothing to really lose in terms of the league table they would be ready to give it a really good go against City.

What transpired was a very flat performance. Granted, they played a very good side, but even so they only occasionally threatened to make themselves a meaningful factor in the game. By the end the defeat felt a little meek.

So when you start to look at the possible reasons for the nerves, you have to wonder whether they were due to Saints’ record against the Premier League big guns under Puel.

When Saints were managed by Mauricio Pochettino and Ronald Koeman they were renowned for going toe-to-toe with the biggest sides, and had some great wins, and bad losses, as a result. If they struggled at all, it was often to grind out more mundane victories against lesser sides.

Under Puel it has been the opposite in terms of Premier League matches. They have done superbly at grinding out hard fought and narrow victories against sides outside of the top six or seven, but have not had the same success against the bigger sides.

Maybe the reason for the nerves is that it has got into the heads of the players.

If that is the case, as Puel may be hinting, then it really needs to be addressed quickly, although admittedly that is easier said than done.

Saints have to play Chelsea, Liverpool, Arsenal and Manchester United before the end of the season. That is four of their remaining seven games.

If Saints are to carry some important momentum into the summer, they will not want to produce another four performances like they did on Saturday.

It was the fact the defeat was so flat against City, that there was no real sense at any point that Saints might win the game, that was so frustrating. There is no better time to have a go than when you are safe in midtable.

Whether it was tactical from Puel, or mental from the players, sitting back and allowing City possession was always a dangerous game.

City are a top side, and of course they do impose themselves, and that factor should not be ignored, but they probably expected a far tougher day than they got.

Despite City’s dominance and probing, they were mainly restricted to half chances during a goalless first period.

The best opening they managed saw David Silva miss the target at the far post after Sergio Aguero’s deflected cross looped up to him.

Indeed, it was actually Saints who had the best opportunity, but Dusan Tadic skied over the bar from 12 yards out after Gabbiadini’s cut back.

It did feel only a matter of time before City would take the lead if they continued to be so on top, and the opener duly arrived ten minutes after the restart.

After Fraser Forster, who had been correctly deemed to have got fingertips on the ball before the man as City appealed for a penalty in the first half, turned a Jesus Navas shot over the bar, City took the lead from the corner.

Vincent Kompany climbed over Maya Yoshida to power a downward header towards goal from six yards out. It bounced up near Forster’s left hand but from such close range he was unable to get anything on it.

City were suddenly all over Saints, yet Puel’s men did have a chance to get level when Tadic picked out Yoshida but he headed wide.

There would be no more mercy from City as they bagged two further goals in the space of three minutes.

They made it 2-0 on 77 minutes with a devastating counter attack. Saints were committed up field and a brilliant early Silva pass set Kevin De Bruyne on his way.

He pushed forward before squaring to Leroy Sane, who slotted it low first time past Forster.

It was quickly 3-0 as De Bruyne stood up a superb chipped cross from the right by-line which found Aguero between Cedric Soares and Jack Stephens to head home from a couple of yards.

Puel must now find a way to quell the nerves.