The joy was pure for the home support at Brentford on Friday evening. For many others, schadenfreude was the emotion as Arsenal were bullied by the Bees. A thought occurred: if they can do that, what might Romelu Lukaku have in store for Ben White?
There are 97.5 million reasons for Arsenal's unconvincing defenders to fear Chelsea's new striker ahead of his second debut for the club at the Emirates Stadium this Sunday.
Leaving aside his pace, technique, vision and intelligence, it is his sheer physical presence. Ivan Toney sought to "get under their skin" but Lukaku could overwhelm them.
The temptation to see him as a blunt instrument to smash defences is obvious.
Perhaps too obvious.
Thomas Tuchel's comments in advance of his arrival appeared to signal that intent.
"I think, with the exit of Olivier Giroud, we could use a player used to playing with their back to goal, whose strength is to keep possession from long balls," he explained.
It is at this point that long-time Lukaku admirers begin to squirm in their seats. He is no siege weapon to be wheeled into place. Stop getting Lukaku wrong, they cry.
Others have done so. Ole Gunnar Solskjaer described him as "a target man" when justifying Manchester United's decision to move in another direction.
But that feels dismissive of his ability to run at defences, his prowess on the counter-attack. Inter had the most fast breaks of any side in Europe's top five leagues last season.
Cutting in off the right wing is a strength, fluidity of movement central to his success. That is why he flourished at Inter and why he needs more than long balls to showcase his game.
Chelsea hit just 8.6 per cent of their passes long last season, only Manchester City opting for that variety of pass less often. It is not their game. The fear sometimes is that the temptation to change is too great when the option is there, the consequences negative.
So it was encouraging that Tuchel gave a much more nuanced response when asked about Lukaku directly upon the completion of his transfer to Stamford Bridge.
"He likes to play physical, he is comfortable playing with his back towards the goal," he reiterated. "But he is also very, very strong in using his speed and pace.
"Romelu has a variety of strengths. He is strong in the air, he will give us a new power when we cross from the side. We do not have to change our style of play to make him shine."
That feels crucial. This is not about Lukaku transforming Chelsea, a team that won the Champions League in May. This is about incremental improvements to their game.
That cross that Kai Havertz could not quite divert into the net? Lukaku will be there. That one-on-one that Timo Werner was not able to finish? Lukaku will be expected to convert.
All 24 of his Serie A goals last season came from within the width of the six-yard box, none of them were from more than 20 yards out. He gives them that presence there now.
Chelsea were the ninth highest scorers in the Premier League last season from open play, underperforming their expected goals by more than any other top-half team. They ranked third for shots from inside the box but only seventh for goals from that zone.
They do not need much.
Indeed, those 12 Premier League clean sheets since Tuchel arrived, three more than any other team in the country, are an indication that - the five-goal aberration against West Brom aside - Chelsea have been rock solid and are close to contending.
The challenge is to avoid repeats of the goalless draws against Wolves, Leeds and Brighton. To ensure that there is no opportunities for those 1-0 victories, seven already in all competitions since Tuchel's first in February, to be surrendered by one mistake.
Lukaku can nudge the dial.
Of course, while a player at his peak - Lukaku is 28 - should be a plug-and-play signing, Tuchel will need to do more than just drop him into this team, he must forge partnerships. The connection with Lautaro Martinez was critical to his success in Italy.
Fortunately, Chelsea is rich with potential.
Werner could benefit from those wall passes, the drawing of men towards Lukaku opening up the left channel for the German to exploit. Christian Pulisic will expect to do the same.
Havertz and Mason Mount can run beyond. Hakim Ziyech might have to wait following his recent injury, but those angled deliveries from the right appear an obvious source of goals.
Perhaps even Cesar Azpilicueta will be tempted to drop a few crosses from deep onto the striker's head in much the same way that he once did for Alvaro Morata.
Lukaku will have options.
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Of course, he will need a connection with his coach, the supporters too. Jose Mourinho stressed the need for him to feel loved to perform at his best.
Tuchel appears keen to put him at the heart of everything. "He has a charisma, he is a good age, he is a leader. Hopefully he can be a leader in our group," he added.
However Chelsea seek to bring out the best in Lukaku, appreciating that he is much more than a mere target-man is a start. As Arsenal could be about to find out, that is just one of the ways in which he is capable of punishing Ben White and the rest this weekend.
Watch Arsenal vs Chelsea live on Sky Sports Premier League from 4pm on Sunday; kick-off 4.30pm
Essential Football Podcast: Will Lukaku get off to a flyer for Chelsea at Arsenal? Plus: Pogba's best role for Man Utd and the lowdown on Watford's new stars
After a blockbuster opening weekend of the Premier League we're gearing up to go again, with Arsenal vs Chelsea a headline fixture and set to feature the Blues' new striker Romelu Lukaku. Peter Smith is joined by Gerard Brand, Adam Smith, Nick Wright, and Ron Walker to look ahead to another big round of games...
PART 1: Will Romelu Lukaku fire Chelsea to a Premier League title challenge? And are Arsenal really in crisis? We assess both sides who go into a London derby in contrasting moods.
PART 2: Paul Pogba starred in Man Utd's win over Leeds with four assists - so how does Ole Gunnar Solskjaer keep getting performances like that out of him? And with Raphael Varane primed for his debut, do Man Utd now have all the pieces in place to become champions?
PART 3: Watford returned to the Premier League in style with a 3-2 win over Aston Villa on the opening weekend. We tell the story behind some of their new signings and examine their prospects this term. Plus we hear how a drive down the M6 was transformative for Brighton defender Shane Duffy…