Manchester United established themselves in second place with a tense 1-0 victory over Tottenham Hotspur at Old Trafford on Saturday afternoon.

Jose Mourinho’s side started well and enjoyed the better of the opening exchanges, but they struggled for the remainder of the first half. And, after a tight second period, Anthony Martial came off the substitutes’ bench to score a late goal, something he's done multiple times this season.

Tottenham competed throughout the match, but Mauricio Pochettino will be disappointed to have left Manchester without a goal or a point. In a tight title race, this defeat could have a negative impact both in terms of the league table and, in the longer term, psychologically.

Here we look at the five key tactical insights from the match.

MOURINHO BRINGS IN THE BACK THREE

Throughout pre-season, one of the main talking points about Manchester United was what formation they would line up in. They began their Premier League campaign by employing the 4-2-3-1 and 4-3-3, but finally switched to a back three for the clash with Tottenham.

Eric Bailly and Phil Jones played on either side of Chris Smalling in a compact defensive trident that rarely looked flustered in its duties.

Their combination of pace, strength and aerial ability made them a tough unit to penetrate, giving David de Gea plenty of protection.

Antonio Valencia and Ashley Young worked well as wing-backs, patrolling their respective flanks, while the switch to 3-4-1-2 allowed Mourinho to field a strike partnership of Romelu Lukaku and Marcus Rashford that both helped the team to defend from the front and provided extra cut and thrust in the final third.

TOTTENHAM DEFEND WELL, AGAIN

The principal tactical characteristic underpinning Spurs’ 4-1 demolition of Liverpool the previous weekend was their defensive play. Pochettino’s side masterfully controlled space, retaining their shape and putting pressure on the ball-player.

They did the same against Manchester United, suffocating the hosts’ hopes of building smooth attacking moves. Dele Alli supported Son Heung-min in the first line of pressure, while they were often aided by one of Moussa Sissoko or Christian Eriksen, depending on which side the ball was on.

Tottenham came close to pulling off a clean sheet and securing a good point away from home against a United side in desperate need of three points. However, they just came up short.

UNITED STRUGGLE TO BUILD EFFECTIVE POSSESSION

While Spurs’ defensive discipline didn’t help, Manchester United made life difficult for themselves when building possession from the back. Perhaps due to the fact they are so unused to playing in a back three together, Bailly, Smalling and Jones didn’t look entirely comfortable on the ball.

One of the major issues was the spacing between the three players. While their compactness helped defensively to nullify Tottenham, they needed to be more expansive in the attacking phase. However, they often remained on the same line, too close together to circulate possession.

They could have learned a thing or two from Spurs in this respect. Toby Alderweireld, Jan Vertonghen and Eric Dier positioned themselves excellently to play around the hosts’ front two and move the ball into midfield, with the former two often driving forward with the ball at feet to try and provoke pressure further up the pitch.

TOTTENHAM MISS KANE

Much will be made of the fact that Tottenham have lost two from two this week, and both defeats coming without the presence of top scorer Harry Kane at the apex of their attack.

While blaming defeat on the striker’s absence would be simplistic, their attack was unusually blunt without him.

Son led the line with his usual combination of intense work ethic and pace, but only rarely troubled a deep, compact United back three.

Alli looked to get in behind, but on the one occasion he had a real chance, he fluffed his lines. In addition, Fernando Llorente lacked the mobility to trouble the opposition when he appeared later in the second half.

Kane is more than a taker of chances; he gives Tottenham attacking options. He can move into the channels, hold the ball up well under pressure, win aerial duels and combines well with team-mates to connect moves.

Without him, Pochettino’s side weren’t able to make full use of their 55 per cent possession.

LUKAKU PROVES HIS WORTH

Questions had been raised over Lukaku’s recent performances, with a four-match goal drought causing some concern. However, the Belgian proved his critics wrong against Spurs, putting in a good second-half display.

Having scorched Hugo Lloris’ fingertips with a drive on the counter, he then hit the post with an accurate header from a wonderfully timed leap. He then set up the winner with a flick-on for Martial to take advantage of.

Lukaku may not be in the form of his life, but he did the best he could with minimal service against Tottenham. And, on another day, he could easily have had two goals of his own to go with his assist.

Premier League