THEY say those who cannot learn from the past are condemned to repeat it.

And while Rangers’ run to the Europa League final will remain the presiding memory of 2021/22, their inability to retain a league title previously won by 25-points was an undisputed failure.

Cast your mind back to the opening day of the season when Celtic lost at Tynecastle and Rangers rolled over Livingston, Steven Gerrard was expected to take his team into the Champions League and continue domestic dominance. Instead, he would depart for Aston Villa three months later and Ange Postecoglou’s Celtic would embark on a long unbeaten run to win the league.

Areas of weakness should inform summer priorities to ensure Giovanni van Bronckhorst is celebrating his first managerial Scottish Premiership title next season. Using StatsBomb data, the Rangers Review has highlighted four key areas that defined the 2021/22 league campaign.

None of the statistics includes penalties. 

Falling behind on the underlying numbers

xG (expected goals) and xG Conceded (expected goals against) are basic football metrics that determine the quality of chances a team is creating and conceding. If you need a refresher, xG is a statistical measurement of the likelihood a chance will turn into a goal.

An xG difference table, therefore, is often used as a barometer of under and over performance. It subtracts a team’s xG Conceded from their xG to form an xG Difference.

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In 2020/21 Rangers topped the xG Difference table with 1.05 per 90 to Celtic’s 1.01. It’s not as convincing a lead as their 25-point margin in the actual league table, given they overperformed in both boxes, but more on that later.

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In 2021/22 Rangers’ xG Difference actually improved from their invincible league campaign. Their 1.21 was bettered significantly by Postecoglou’s side who clocked 1.75 per 90, a far stronger total.

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What does this mean? Celtic created a higher quality and conceded a lower quality of chances throughout the season.

A closer look at the team’s attacking and defensive comparisons demonstrates the small, dictating differences that saw the league title head to Glasgow’s East end. Notice a higher xG per 90 (2.28 to 1.89), xG/Shot and Clear Shots. Celtic created a higher number of chances and better quality of opportunity.

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Defensively, the difference is again small but meaningful. Celtic conceded a lower xG and xG/Shot, although Rangers were slightly more resolute when defending counterattacks. The eventual league winners were also marginally more aggressive and pressed with greater intensity (PPDA).

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Underperforming in front of goal

As Rangers romped to a 55th league title, their record-breaking defence negated the need to win by high-scoring margins. Without that same resolve in 2021/22 and alongside a reversion to the mean in front of goal, their attacking frailties were exposed. 

In 2020/21 Rangers scored 85 goals from 67.47xG, in 2021/22 they scored 71 goals from 73.98xG. Despite creating a better quality of chance last season than in Gerrard’s title-winning campaign, they scored 14 fewer goals. This shouldn’t be a huge surprise, given they notched around 17 more goals than the numbers suggest they should have in 2020/21. These statistics do not include penalties.

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Why? In 2020/21 several players overperformed their underlying numbers, 10 to be exact. Ianis Hagi returned seven goals and 10 assists from 5.67xG and 6.02xG assisted, Kemar Roofe scored 14 goals and made three assists from 10.18xG and 1.55xG assisted.

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Fast forward to the latest campaign and the table is a whole lot more underwhelming. Roofe and Hagi are nowhere to be seen at the top and only one member of the forward line, Ryan Kent, scored and created more than he should have statistically.

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In 2021/22 Hagi had two goals and no assists from 2.74xG and 1.74xG assisted, while Roofe had 10 goals (three of which were penalties compared to none in 2020/21) and no assists from 6.16xG and 1.63xG assisted.

One of the main differences between Rangers’ 2019/2020 season and 2020/21 was found in the quality of squad depth. Roofe scored goals from the right-sided forward position nobody had previously, while Hagi added numbers from midfield.

Without these two key performers, and given the only offensive threat added in the transfer window was Fashion Sakala, there was a severe lack of goalscorers on the pitch at times.

Starting fast and ending strong  

One of the key weekends that determined the title’s location came in late January. Rangers surrendered a late lead to draw at Ross County and Celtic snatched a late winner to win against Dundee United.

Late goals were a factor in Celtic’s season and absent from Rangers’. When comparing the two team’s trendline, which shows when the respective teams had opportunities to score, two other time periods appear crucial.

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Rangers were peaking in the 80th minute while Celtic usually had their best spell around the half-hour mark.

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Were Celtic’s opponents simply more worn down by the late stages having faced a faster start? Did Rangers often leave it far too late to raise their tempo?

Tempo is hard to gauge and quantify. The eye test certainly detected lethargic signs and slow starts that proved costly come May, while prior to the departure of Gerrard the Ibrox side conceded the game's first goal with worrying repetition. At this time, their manager lamented the lack of a complete “90-minute performance”.

A goalkeeping conundrum 

Allan McGregor saved 5.22 goals above average in 2020/21.

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That number dropped to 0.94 in 2021/22.

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He was worth five goals as the side won 55 and just under one last season. Having endured a drop off at the very time his team’s form started to flounder in February.

Across the board, Rangers’ goals conceded to xG ratio is a similar story in defence as in attack. Again not including penalties, from an xG Conceded of 26.36 in 2020/21 only 12 goals were let in.

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Last season, from a very similar xG Conceded of 26.34, 29 goals were shipped.

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In many ways, last season feels like a perfect storm. A managerial change, style shift and key injuries. Equally, the reversion to the mean in both boxes should have been anticipated and catered for.

If Rangers learn from the past, adding goals to their starting 11, replacing Allan McGregor in goals and freshening the side up to improve their tempo, they can be confident ahead of the new domestic season. Without alterations, 2022/23 could prove a painful encore.