There was a time in the not-too-distant past when Gabriel Jesus, at the age of just 19, looked like the top dog in Manchester City's striking department. Right now, at least, that is not the case.
Sergio Aguero was charged with watching and learning from the young Brazil striker, particularly when it came to pressing and movement off the ball, and it appeared for a while as though the Argentine's days at City were numbered.
Yet Aguero has improved to such an extent that he is now playing the best football of his career and is firmly at the top of the pecking order once again. On Friday it was announced that he has signed a contract extension that will keep him at the Etihad Stadium until 2021.
That comes amid a difficult run for Jesus, who enjoyed a flying start to his City career when he arrived midway through the 2016-17 season but has been hampered by injuries and other set-backs since.
Still just 21, it is understandable that he will suffer rough patches, and it is inevitable that he will hit form again.
But for now he is struggling; he has scored one goal in his seven appearances so far this season and he has been criticised by supporters in recent weeks, charged with not offering enough to the team when he is not hitting the back of the net.
It was a similar story for Brazil during the summer, when fans called for him to be dropped for Roberto Firmino.
His coaches and team-mates for both club and country certainly do value his efforts, however. During the summer his Brazilan colleagues nicknamed him "o fenomeno" due to his work-rate, and indeed he covered more ground than any of them in their third group match against Serbia - 10.26km.
And Guardiola, speaking on Friday, insists there is nobody better in that regard.
"His movements, his high pressing is the best in the world," the Catalan said when asked what Jesus has brought to the team of late.
Guardiola was initially defensive when it was asked whether Jesus was short on confidence - "he's happy" - and when asked to rate his performances this season - "good". But after praising his work-rate the City boss did highlight the specific areas in which he needs to improve.
"He's still a young player and when they are young they have a gap to improve and we are going to help him. In the final third, in taking decisions, in short spaces, but the most important thing for Gabriel is always the desire to improve, paying attention in training sessions to know what he can improve, and he will get it."
Despite Guardiola's public protestations, Jesus has looked short of confidence so far this season, to the extent that he has missed seven big chances in his two starts and three substitute appearances in the Premier League. That is more than anybody else.
Guardiola has vowed to help Jesus improve as a player, although personal circumstances may not be too helpful in his quest to find his feet again.
He enjoyed the first few months of his new life in Manchester as something of a novelty; he and his close group of friends rented a city centre apartment and regularly ventured out to mingle with fans, before returning at night to play games on their consoles and iPads.
But those friends were denied re-entry to the United Kingdom after they went back to Brazil for Christmas, and have been unable to obtain visas since. That has left Jesus more isolated as he gets to grips with living in the north west, and with day-to-day life miles from home.
Jesus' injuries, which handed Aguero opportunities to prove his value to Guardiola, have also clearly hampered his own progress. The broken foot just weeks after his City debut and the knee injury he sustained midway through last season disrupted his rhythm.
And when it comes to some of his struggles this season, he may not have been helped by Guardiola's desire to try new things on the pitch. Jesus, albeit while new to English football and with his friends around him, played some of his best football while flanked by Leroy Sane and Raheem Sterling, as City attacked at pace in Guardiola's first season against teams that did not sit as deep as they do now.
In recent weeks he has had Riyad Mahrez and Bernardo Silva to his right, with both men either favouring a cut-back onto their left foot or a step-over before delivering the ball into the area. This season he has actually looked better when playing alongside Aguero, who is assuming more and more responsibility himself.
The impact of Jesus' pressing may have also become lost on those outside the City dressing room. When the Brazilian burst onto the scene Aguero was struggling in that regard, while Sane and Sterling were also getting to grips with Guardiola's demands.
Jesus shone brighter than those three at the time, but during the course of last season they have kicked on, and new players have been brought in, while injuries and off-the-field issues have held the former Palmeiras man back.
Those who have written Jesus off on social media have been reminded of his sharpest moments - not least his last-gasp goal at Southampton that clinched City's 100-point season - and he will surely provide plenty of fresh examples in the future.
Guardiola had more advice for Jesus, too. "In the good moments you have to be stable and in the bad moments you have to say, 'OK I am here again', we have to learn from the best athletes in the world. You have to face the new challenges."
It was always a measure of Jesus' potential that he was the one teaching Aguero new tricks, but at the moment it is the youngster who will be taking notes from his senior strike partner, namely on how to deal with set-backs at Manchester City.