Arsenal made changes but were undone by a familiar failing during a 1-1 draw with Everton at Goodison Park on Saturday.
A smart goal from Leandro Trossard, one of the many rotated into an altered starting XI ahead of facing Real Madrid in the UEFA Champions League, gave Arsenal a 34th-minute lead. Unfortunately, Myles Lewis-Skelly was adjudged to have felled Jack Harrison four minutes after the break, allowing Iliman Ndiaye to equalise from the penalty spot.
It was yet another costly infraction from bright young thing Lewis-Skelly, who has already seen his fare share of red cards this season. Yes, some of the decisions against the 18-year-old have been harsh, but there's no denying the cost of Arsenal's inability to stay on the right side of match officials.
That cost is measured in points, with leaders Liverpool now having one hand firmly on the Premier League title. Arsenal's rivals aren't simply running away with the big prize because of a lack of discipline among the Gunners.
Inconsistency in attacking areas, mostly due to the absence of a true centre-forward and inconsistent creative output, has also left Arsenal trailing. Those qualities were stamped all over a drab first half when the visitors failed to fully press their advantage against overly cautious and below-par opposition.
At least Mikel Arteta can take consolation from easing the workload on key players ahead of the visit from Champions League royalty. It was a balancing act managed well, as star men like Bukayo Saka and Martin Odegaard still got valuable minutes, but should be fresh after less-than full domestic duty.
Positives & negatives from Arsenal's 1-1 draw at Everton

Positive #1: Leandro Trossard shows signs of life
It seems like an age since Trossard showed his value, but the Belgian offered a timely reminder on the blue half of Merseyside. His finish to cap a slick and swift counter, was cool, composed and precise.
This was Trossard at his best. He's always been more goalscorer than goal provider. The distinction is marked by key qualities the Gunners have been missing for too long.
Those qualities include a sure and neat first touch, along with calmness in front of goal. That same serenity makes efficient finishing possible.
Finding the net consistently is what separates Liverpool from Arsenal. At least in part. So it's good news Trossard has rediscovered the scoring touch before two games against Real.
Now if Arsenal could only find a way to manufacture more chances before that season-defining last-eight tie...
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