You can tell when Raheem Sterling is at the very top of his game. Just watch the reaction of opposition defenders when he gets the ball.
When he's on it, opponents visibly steel themselves: muscles tighten, shoulders dart back, eyes narrow. Here he comes, get your head on, this could get messy.
At West Ham last Sunday, his every touch provoked panic in a Hammers back line that was twisted, turned and run ragged by the speed, determination and direct action on display from the Chelsea forward.
He would ultimately end up on the losing side at London Stadium, but his man-of-the-match performance drew widescale plaudits. "Scintillating" was the word Micah Richards used to describe him on ONNTV Radio 5 Live's Monday Night Club. He was the "shining light" according to Garth Crooks in his team of the week.
Such terms have been in rare supply of late when discussing the England international, with last season - his first at Chelsea - a failure of fitness and form, yielding his worst attacking returns in a decade.
But after giving his first club Liverpool the runaround on opening weekend, he now has two successive high-calibre games to brandish at his seemingly ever-present and emboldened band of detractors.
It is too small a sample size by which to get carried away, but it does hint at a refocused, re-energised player, keen to reassert his worth to his critics and re-establish himself as a leading figure for club and country.
To listen to the 28-year-old in pre-season before this campaign, it is clear he has not left it to chance.
Speaking about his travails during 2022-23, Sterling laid part of the blame on his diet and the gaining of extra weight that led to hamstring problems in the middle of the campaign.
These caused him to miss six league games, the FA Cup third-round loss to Manchester City - from whom Chelsea had paid up to £50m to sign him the previous summer - and two England Euro 2024 qualifiers in March.
However, forgoing detail, he says he has now rectified his food intake, with one simple rule - don't eat as much - and the early results are clear to see.
"At the end of last season, I changed a bit of my diet and went to do something a bit different to what I have done before," he said. "I am eating a little bit less.
"Pre-season is a good time to get the body right and I am in a great place."
Liverpool and West Ham have felt the force of that already.
Sterling presented both with a dilemma with his intelligent pairing up with the wing-back on the right (Reece James against the Reds, Malo Gusto against the Hammers), regularly taking up space between midfield and defence for zipped passes his way, making him hard to mark and creating the potential for overloads.
What makes the strategy work to its fullest is Sterling's rediscovered confidence to quickly turn and run at speed with a ball completely under his spell, beating men or drawing them to him to create room for others.
It was Sterling's intelligent run in behind the Liverpool defence and blocked cross that led to the corner from which Chelsea levelled on opening weekend.
He stepped it up another level at West Ham, producing six successful dribbles in the game from 12 attempted (the rest of the Chelsea side combined produced 19), one of which led to the penalty that Alphonse Areola saved to prevent the Blues taking a crucial 2-0 lead.
According to statistics site fbref.com, he produced a game-high 10 progressive carries and seven shot-creating actions at the London Stadium.
"This is the Raheem we know and love and want to see week in, week out," Richards told the Monday Night Club.
"He looks so fresh now. What I love about Raheem is as a winger, just kick the ball and run. Everyone tries to be fancy now and comes with these buzzwords like 'in the pocket', 'between the lines' - but as a winger you just get the ball and run at your full-back. That is what made him the player he is today."
There was precious little of this to see during a chastening 2022-23, in which Sterling had sought a fresh start after a trophy-laden seven seasons at Manchester City but instead found himself one of many expensive misfits in a club struggling for cohesion both on and off the pitch.
Sterling was the first major signing following the Todd Boehly-led takeover of the club, leading the way in a season that saw around £550m spent on new players.
The Blues would go through four managers en route to a 12th-placed finish - their lowest since ending the 1993-94 season in 14th place.
Like many of his team-mates, Sterling struggled, partly due to injury but also because he lacked a consistent tactical message or a settled place in a team seemingly in constant churn.
Chelsea's inexplicable failure to bring in a suitable number nine despite their lavish spending meant Sterling had to take the ill-suited role for around half his appearances. The rest were split between the right and left wings.
This summer has seen another huge turnover in the squad to further clear out some of the old guard and drastically reduce the average age. Injuries have played a part in this, but Sunday's side at West Ham contained six players aged 21 or younger.
The evidence so far is that new boss Mauricio Pochettino has faith in Sterling, who could well be entering the next phase of his career.
After hitting the scene at such a tender age at Liverpool before becoming part of a City behemoth packed with authoritative characters, is it now time for him to lead by example as a senior figure in a side so full of young talent in need of guidance?
As anyone who has read his 2018 piece in The Players' Tribune can attest, Sterling is emotionally intelligent and self-aware. His life has taught him to be resilient, driven and grateful. He's added his own experiences to lessons passed down to him - ones he can now impart to others.
After such a splurge on players, Chelsea inevitably had to settle down and work with what they now have and a player like Sterling, with 10 major medals including four for the Premier League, will be invaluable in helping mould them into winners.
And then there's England.
With such an abundance of talent available, Sterling's problems last year saw him slip down the pecking order for a place in the Three Lions forward line.
He didn't even make the squad for June's Euro 2024 qualifiers against Malta and North Macedonia as a result of a mutual decision based on how best to manage the demands on his then fragile physical state.
He has had to watch on as the likes of Bukayo Saka, Jack Grealish, Marcus Rashford and Phil Foden further their own claims to operate either side of Harry Kane.
Gareth Southgate knows exactly what he can get from a fit and firing Sterling, though. He has been national team boss for 55 of the forward's 82 caps, during which he has scored 18 times. He has captained the side four times on Southgate's watch.
It wasn't long ago that Sterling was a key member of the England side that came within a penalty kick or two of ending their long wait for a major trophy at Euro 2020.
It seems inconceivable that Southgate would overlook the Chelsea man when on top form, and if the early signs of this season are anything to go by, that time is coming.
But if he does need a gauge for whether Sterling is ready to return to the national fold, he need only observe the reaction of Premier League defenders when the forward get the ball at his feet.
