Rangers' zonal marking explained: How PSV claimed aerial ascendancy at Ibrox

Giovanni van Bronckhorst’s side finished the game with an xG (expected goals) of 0.85 to the visitor's 1.33. During a tight 90 minutes, Ruud van Nistelrooy’s men marginally shaded the quality of opportunities in front of goal.

Crucially, they created 0.36xG from set-pieces compared to Rangers' 0.06xG, despite having just one more corner and four fewer attacking free-kicks.

But numbers only tell part of the story. Although Rangers scored a fortuitous second themselves through Tom Lawrence, they conceded two goals from just five PSV corners. Having denied their Dutch opponents in open play and come from behind to lead the tie, that will prove a source of frustration heading into next week's second leg.

PSV took three inswinging corners, one outswinging and one short corner. As demonstrated by the touch map below, the hosts won first contact on three of four occasions. Three inswinging first-half deliveries targeted the front post (red) from the left and a late outswinging equaliser from the right was directed towards the centre of the box.

At each corner, the same six PSV players attacked the box. Ibrahim Sangaré (No.6) André Ramalho (No.5) Luuk de Jong (No.9) Armando Obispo (No.4) Erick Gutiérrez (No.15) and Jordan Teze (No.3).

Rangers defended each set-piece with nine men in the same zonal set-up, until late substitutions changed the personnel for Obispo’s goal.

Malik Tillman (No.71) and Borna Barisic (No.31) guarded the front and back post. John Lundstram (No.4) Connor Goldson (No.6) and James Sands (No.19) were staggered along the six-yard line. Steven Davis (No.10), James Tavernier (No.2) and Antonio Colak (No.9) sat higher, in an attempt to block runners. Tom Lawrence (No.11) was free at the edge, presumably to protect against any cut-backs.

A zonal marking system sees players defend an area of the box, rather than marking up man-for-man.

Theoretically, this should ensure a team isn’t pulled apart by the opponent’s movement while covering all areas of the box. The strongest defensive headers of the ball will usually be positioned in the first line closer to goal, as shown above.

This is all well and good, but if the second line of defence doesn’t block runs and stop the opposition's strongest headers from building momentum, often stationed at the edge of the box to afford room for a run-up, the zonal system can simply lead to free headers.

For both goals, this second line of defence was outnumbered and overloaded.

PSV had three corners leading up to their opener. Cody Gakpo’s delivery on 31 minutes was cleared by Tillman…

Two minutes later, the US midfielder skuffed a clearance that Jon McLaughlin gathered…

When the visitors got a third corner in quick succession, their group of attackers started closer to goal.

Compare their positioning as Gakpo crosses at 31 minutes…

33 minutes…

And 36...

Gakpo stuttered when taking his run-up for the opener. Whether by product or design, it ensured the attacking unit was closer to goal, and to the eventual cross, as they opened the scoring…

Although Obispo, who scored the second, doesn’t connect prior to Sangare’s finish, the run he makes likely puts Tillman off and preempts his goal later in the game.

Below, Rangers are three-vs-two at the edge of the box. Tavernier is marking Obispo while Davis and Sands double up on de Jong.

As outlined above, it’s likely not the captain’s job to win first contact, but to blockade his marker’s run. However, de Jong returns the favour and blocks Tavernier as Obispo runs around the front, allowing his teammate to attack the ball untracked. Just like zonal marking, man-for-man defending can be exploited.

Rangers win first contact through Goldson but after a deflection, Sangare can finish unmarked. Davis, Colak and even Tom Lawrence should arguably have reacted quicker to close the space PSV score from.

Only two corners followed in the second half. The first of which sees Rangers employ the same zonal set-up, with Colak, Davis and Tavernier outnumbered at the edge of the area trying to block runners.

But the visitors take a short corner that Sands eventually clears.

Then, 12 minutes from time with the score at 2-1, PSV won their first right-sided corner of the game that Obispo would score from.

The hosts are again outnumbered at the edge of the box, favouring to keep a line of five across the six-yard line.

They have nine men to PSV’s six in the box. Scott Wright and Glen Kamara have been brought on for Davis and Tillman, meaning Tavernier guards the right post in place of Tillman...

Zooming in closer, we can see that Colak is blocking the run of de Jong while Lawrence marks Sangare, but Gutiérrez and Obispo are totally free…

This is the first corner taken after a double substitution, and the only time Rangers were left two-vs-four at the back post. This allows the defender a clean run and jump at Gakpo’s cross…

Goldson is at a real disadvantage to contest the cross. He’s side-on and jumping from a standing start, while Obispo has yards to build momentum and attack the cross.

So who is to blame? Size does of course play a factor at set-pieces and PSV are a big team, but Rangers simply did not disrupt the momentum of runners sufficiently to protect their first line of defence, particularly for the equalising goal.

Obispo’s run for the opener should have provided a warning, but as he made it 2-2, the PSV No.4 could attack the ball untracked. By leaving themselves outnumbered at the edge of the box, Rangers' zonal system was exposed and allowed the visitors to attack the ball far too comfortably.

“We have great headers of the ball in our team and the delivery was good,” van Nistelrooy said after the game.

“We attacked the spaces that we’d planned to before the game and executed that well."

Set-pieces will play a part next week in Eindhoven and if Rangers are to reach the Champions League group stages, they must ensure no advantage is handed out by their zonal set-up.