Pep Guardiola, prepping for Manchester City's Champions League test at Atalanta on Wednesday, while also undoubtedly plotting for the weekend's titanic showdown at Anfield, will have seen a familiar and unwelcome sight.
Just under an hour into Liverpool's 2-1 home victory over Genk on Tuesday, Alex Oxlade-Chamberlain collected Mohamed Salah's fleet-footed lay-off and swivelled before driving a shot into the bottom corner.
That goal, his fourth in the last three starts, was the winner and crowned a dynamic performance that served as a throwback of the midfielder's best form prior to sustaining multiple ligament damage in April 2018.
That robust, ball-carrying and line-breaking version of "Ox" is one Guardiola knows well and will not want to see in Jurgen Klopp's starting XI on Sunday. After all, the player's last two goals for Liverpool prior to his lengthy sideline spell came during inspired displays against City.
The first -- ghosting past Fernandinho before guiding an early rocket beyond Ederson into the bottom corner -- was a highlight in the 4-3 league win at Anfield in Jan. 2018, which ended the visitors' 22-match unbeaten run in the Premier League.
The 26-year-old produced more of the same in Liverpool's 3-0 home victory in the Champions League quarterfinal first-leg, which was the club's first game since Philippe Coutinho's move to Barcelona.
Ox took the Brazilian's spot in the starting 11 and also inherited the status of City's slayer-in-chief, thundering in an almighty hit from 25 yards out with no City player closing him down.
He was electric in the high-pressured reverse fixture at the Etihad too, driving Liverpool forward in possession and ultimately into the semifinals.
In those matches against City, Klopp plumped for the "Fab Four" in attack, playing the England international as a supporting act to Sadio Mane, Roberto Firmino and Salah.
However, that 2017-18 edition of Liverpool was powered by their offensive might and they have since been successful by adopting a steely approach with more surety throughout the squad. They no longer need to blitz their way to wins with a stronger spine and greater game management.
Meetings with Man City have taken on a heightened importance with the Merseysiders manoeuvring closer to a league title, missing out to their intense adversaries by a point last season.
The goalless draw at Anfield last season was tetchy and risk averse in a departure from the breathless encounters between England and Europe's pre-eminent forces.
It will be interesting to note then whether Klopp sticks to his big-game trio of Fabinho, Jordan Henderson and Georginio Wijnaldum in the centre of the park on Sunday, or twists towards giving City an Oxlade-Chamberlain-shaped nightmare to contend with.
Against Genk, the German said he "wanted to have Ox in-between the lines, to turn, to create problems for them and space for us," which worked to Liverpool's advantage as it has done in the past against Guardiola's exceptional side.
During the player's previous two starts -- in the 4-1 victory away at Genk and the barely believable 5-5 Carabao Cup draw with Arsenal at Anfield which Liverpool won on penalties -- he produced typically stunning goals, but his all-round game was still lacking.
"I was not near my own personal level of where I want to be," Oxlade-Chamberlain admitted after the shootout triumph against his former club.
"I put in a good shift and run a lot. I watch the boys on a weekend and I know what it is about here -- you have got to be at a really high, physical level to go and put in a performances like that. I need to keep pushing myself."
Oxlade-Chamberlain did just that on Tuesday night, delivering a luminary showing in a fluid role. His versatility saw him operate on the left, right, as a false nine and attacking central midfielder.
The dynamo possesses a different skill-set -- his threat from outside the box, strength in the dribble, ability to power past or commit markers -- to the rest of Klopp's more disciplined options to operate in front of Fabinho. With teams intent on stifling the creative influence of Liverpool's full-backs, his expertise in conjuring decisive moments out of minimal opportunities would be an asset.
Naby Keita, who will also be hoping to force his way into the manager's thoughts for the biggest game of Liverpool's season thus far, impressed against Genk too, but is still searching for consistency.
If Klopp does break convention and switches things up in midfield, the wisdom at present is that Ox will be the beneficiary.
Given Guardiola's jibes against the league leaders -- six points separate the sides -- he already seems on edge ahead of the top-of-the-table tussle and the prospect of a recharged Oxlade-Chamberlain running at City is unlikely to put him at ease.