Manchester United vs. Southampton: Louis Van Gaal and Ronald Koeman Reaction

In a clash between Dutch masterminds, Ronald Koeman came out the victor at Old Trafford on Sunday as his Southampton side stole a 1-0victory from Louis van Gaal's Manchester United.   

It's a win that proves the Saints may well be ready for top-four contention, and Koeman was keen to emphasise as much in his post-match comments, per the official Premier League Twitter account:

Dusan Tadic came off the bench to drill the winner past David de Gea in the 69th minute, but tactics proved key to Koeman's victory as the hosts were largely nullified in front of a home crowd.     

The manager went on to add that his team were fortunate at times. Juan Mata in particular had several superb chances to break United's deadlock, with Koeman touching on his hopes to challenge the Premier League big guns, per Neil Johnston of BBC Sport:

"

Juan Mata had two big chances at the end, we missed that luck in the home game and we got that today. If you play against a big side you need spirit and quality but you also need belief in yourself and your team-mates and we showed that today. We have had good organisation all season, we have 11 clean sheets in 21 games and that is key to being successful.

We have aspirations [of securing a European finish], but at the beginning of the season you have to wait. Now we can say we fight for a European place. The top five or six, we will fight until the last game.

"

Koeman made sure to congratulate his goalscorer after claiming the Saints' first Old Trafford win in 27 years, too, telling BBC Sport: "I don't like players taking off their shirt. It is a yellow card but he was fantastic in the final half hour. He made the difference when he came in and I am proud of him."

Southampton's boss wasn't the only manager to praise the visitors' defence, however, as Van Gaal noted their ability to withstand assault, according to Samuel Luckhurst of the Manchester Evening News:

United may rightly be dismayed with Sunday's loss, especially when considering hopes were so high after seeing a wealth of players return to fitness in the past week.

That being said, there was still no sign of Radamel Falcao. Van Gaal highlighted the need for rotation during such a packed period, but some may feel the Colombian would have made a difference:

Luke Shaw has experienced recurring injury issues this season and was taken off in place of Tyler Blackett after 63 minutes, but the United manager assured it wasn't an injury-related change:

The result means Manchester United drop to third and have lost a major step in their bid to return to the English elite, while Southampton look to be soaring once more.

Nevertheless, Van Gaal told Match of the Day (h/t BBC Sport) that he felt his side were the superior outfit: 

"

We played a much better game than Southampton. They were lucky to score out of nothing. That is very disappointing. We didn't create so much but we dominated the game. 

We have to improve. We have to make better choices with the ball but you also have to take into account that the opponent was well organised today.

"

One surrounding piece of controversy at Old Trafford this season has been the helmsman's insistence on playing with a back three, as he did on Sunday.

David Moyes' sole season in charge of Manchester United was largely seen as a dismal one, but as the Daily Mail's Match Zone shows, Van Gaal has taken an identical points tally to the Scot after their first 21 games in charge:

When quizzed on that result, per BBC Sport, Van Gaal gave a frosty response:

"

Yes. You have waited until this moment to put this question? This moment I have the same points as David Moyes? OK.

We have to be better, we have to improve and that is why we are working hard and working on that. I have said already we were the dominating team, but we have to create more when you are the dominating team. I think Southampton came for the draw, and went away with the victory.

"

Some feel a back four is the optimal tactic, but when asked if he believes that to be the case, Van Gaal again asserted that his team were the stronger force, per Tom Williams of Agence France-Presse:

In the end, nothing can be taken away from Koeman and Southampton as a collective, who showed that their organisation and players individually are capable of making the step up this season.

Van Gaal is regarded as among the finest tactical minds in the sport, but he was ultimately outclassed on Sunday, suffering a drop through the Premier League standings as a result.