Football writer Tom Hancock reflects on the lessons learned from Wednesday's Premier League matches, which featured the league leaders, one of their closest challengers and the reigning champions.

Three words have defined Arsenal’s three successive second-place Premier League finishes: strength in depth. If the Gunners were to end their 22-year title drought this season, they were going to have to equip themselves better to deal with the injuries which have derailed their recent pushes for glory.

Following a flurry of summer transfer activity worth almost £250million, Mikel Arteta's squad certainly looked ready for perhaps their strongest title assault yet. And in beating Brentford 2-0 on Wednesday to restore their five-point lead over Manchester City at the Premier League summit and extend their unbeaten run to 18 games in all competitions, Arsenal showed just how much quality they have at their disposal.

ack in action barely 72 hours after Sunday’s 1-1 draw at Chelsea, Arteta made three changes to his starting 11 for their third consecutive London derby in the Premier League.

Jurrien Timber was given a well-deserved rest at right-back, affording Ben White his first league appearance since Matchweek 1. Meanwhile, captain Martin Odegaard made his first start since returning from injury, in place of Eberechi Eze, and summer signing Noni Madueke came into the side for Bukayo Saka.

With the fit-again Viktor Gyokeres and Gabriel Jesus among the substitutes on a stacked bench also featuring the rested Eze and Saka, Arteta will have been more than confident in his ability to change the course of the game had things not gone to plan at Emirates Stadium. As it transpired, that wasn’t necessary.

Notably, it was Madueke and White who combined to set up the opening goal for Mikel Merino - himself a stand-in striker - on 11 minutes. Madueke was a constant thorn in Brentford’s side for the hour or so he played before making way for Saka, who sealed the three points in stoppage time.

At the other end, Brentford's former goalkeeper David Raya had denied Kevin Schade an equaliser at 1-0 with a phenomenal fingertip save.

Man-of-the-match Merino’s assist for Saka made it two or more goal contributions for the Spaniard for the fifth time in an Arsenal shirt in all competitions, and Arteta was full of praise for a player who has well and truly stepped up to the plate outside his natural midfield position.

"We lost Viktor [Gyokeres], Kai [Havertz] was out and Gabriel Jesus was out," said the Arsenal manager.

"He [Merino] did it last year really, really well. I think this season, he's probably taken it to another step because he's able to do even more things. So, I think the team is really grateful, and he's enjoying it."

Sterner tests will come – Arsenal face a rampant Aston Villa away on Saturday and also at home before the end of 2025 – and Arteta will hope for better injury luck. The Gunners lost Cristhian Mosquera – whose fellow centre-backs Gabriel and William Saliba were already sidelined – and Declan Rice during the course of this match.

Nonetheless, the Gunners passed the strength-in-depth test consummately, keeping an eighth clean sheet in 14 Premier League matches this season, despite their defensive injury woes, and further solidifying their unquestionable title credentials.

Chelsea's rotation results in costly slip-up

By contrast, Chelsea’s lack of strength in depth was exposed as the Blues suffered a major blow to their title ambitions by going down 3-1 away to Leeds United.

With Enzo Maresca making five changes to his starting line-up and missing the likes of Moises Caicedo and Reece James, Chelsea looked a shadow of the team who had held Arsenal to a 1-1 draw with 10 men last time out.

The Blues headed to Elland Road having lost only one of their previous 12 games in all competitions, but goals from Jaka Bijol and Ao Tanaka ensured that Leeds, on a run of four straight Premier League defeats, went in at half-time in the driving seat.

The visitors improved after the break, Pedro Neto pulling one back early in the second half, while Cole Palmer’s return from the bench after more than two months out was a major positive.

However, Leeds’ sustained attacking threat paid dividends as Noah Okafor capitalised on Tosin Adarabioyo's hesitation on the ball in his own box to allow Dominic Calvert-Lewin to poke the ball into an empty net.

Speaking after a disappointing night in West Yorkshire, Maresca appeared to acknowledge that a drop-off was inevitable given Chelsea’s rotation.

The Blues' head coach said: "They were better than us in all aspects; they deserved to win the game. There is nothing we can take from this game; the only thing we can do is to try and understand what we did and then reset.

"We [performed] so well against Arsenal and Barcelona; it doesn't mean we are going to always perform in the same way because of the situation you have to manage, the players you have to rotate. The level isn't always going to be the same."

For Chelsea, who now trail leaders Arsenal by nine points, this was a night which laid bare their flaws in multiple departments and suggested that they are still a fair way off challenging for a first Premier League title in almost a decade.

For Leeds, the result provides much-needed respite for under-pressure manager Daniel Farke ahead of Saturday’s home clash with Liverpool.

Liverpool stutter as Slot sticks with Salah-less line-up

Arne Slot’s decision to make just one change to his side against Sunderland – Andy Robertson coming in for Milos Kerkez at left-back – might suggest that the Liverpool boss feels unable to rotate as much as he’d like to.

The Dutchman showed his decisiveness again by leaving Mohamed Salah on the bench for the second game running, something the Egyptian had never previously experienced in almost nine-and-a-half Premier League campaigns with the Reds.

Slot's decision had been justified on Sunday with their 2-0 victory at West Ham United. But this time the Reds' badly faltering title defence stuttered once more as they were held to a 1-1 draw by Sunderland at Anfield.

When Chemsdine Talbi's deflected effort put the Black Cats ahead on 67 minutes, it looked like it might be another case of Merseyside misery for Liverpool, who had lost 4-1 to PSV Eindhoven and 3-0 to Nottingham Forest in their last two home outings. It wasn’t to be quite as sorry a story this time out, though.

Florian Wirtz thought he finally had scored his first Liverpool goal – it ultimately went down as a Nordi Mukiele own goal – but the German can take heart from forcing the Reds' 81st-minute equaliser with a skilful jaunt through the Sunderland defence, as the £100m summer arrival showed more of his class following a difficult start to his Premier League career.

And Wirtz’s effort was certainly appreciated by his boss. Speaking at full-time, Slot said: “There’s a difference between hitting a shot from 11-12 yards and hitting a shot from 20 yards. He might’ve been lucky with the way it went in, but it was a good chance for him to score.”

With just one win in five in all competitions, Liverpool are far from back on track – they could easily have lost this game but for Federico Chiesa’s crucial goal-line block to deny Wilson Isidor in stoppage time – but Slot can take encouragement from seeing his team fight back to take points from a losing position for the first time in the league since Matchweek 2.

Meanwhile, Sunderland’s immensely impressive return to the top flight continues: they have now played five of the Premier League’s current top eight and not lost to any of them. (premierleague.com)