Former Arsenal defender Gabriel has been a mainstay of the Valencia backline this season, impressing many observers.
And he may come up against Shkodran Mustafi on Thursday night as Arsenal visit the Mestalla - with the contrast in performances of the two players telling.
The La Liga defender, who faces his old club on Thursday in the crucial second leg of the Europa League semi-final with the Gunners leading 3-1 from the first leg, has left many fans wondering why Gabriel was sold only for the error-prone German to replace him for £35m.
The 28-year-old former Arsenal centre-back joined the La Liga club in a £10million deal, two-and-half years after moving to the Emirates from Villarreal.
However, during his time at the club the Brazilian failed to fully establish himself as a regular at the back and was the focus of criticism aimed at the Gunners defence.
The Sao Paolo born defender - who grew up in a wooden house in a favela back in Brazil - did not have the best of times in North London with his spell viewed as a difficult period in his career after repeatedly coming under fire for his performances.
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The Brazilian was also seen as something of a hot-head, which manifested itself when he was sent off against Chelsea for a tussle with Diego Costa.
He left Arsenal in 2017, having made 26 appearances and won two FA Cups, going on to sign a five-year deal with Valencia.
Yet since joining Valencia, 28-year-old Gabriel has gone from strength to strength, guiding his side to the last four of the Europa League.
With Gabriel in the side the Mestalla-based outfit have one of the best defensive records in La Liga with the ex-Gunner making 28 appearances.
Gabriel himself has admitted his time in London toughened him up. He has also reflected that he needed to show more leadership qualities which he has done during his time at the Mestalla in beconing one of the club's senior players.
Contrast this with the unfortunate Mustafi - who had moved the other way from Valencia to the Emirates a year prior in 2016.
The 27-year-old got off to a good start but has failed to kick-on and impress during his three years at the Emirates.
If anything he has regressed while losing confidence. Every mistake is amplified and he appears a shell of the player he promised to be when he first came to the Emirates.
During this season he's given away two cheap penalties twice costing the Gunners victory.
In October, during a 2-2 draw at Crystal Palace, Mustafi hacked down Cheikhou Kouyate in the box to give the hosts the chance to go 1-0 ahead, which they took.
In the North London derby against Tottenham in March Arsenal were winning 1-0 until Mustafi needlessly pushed Harry Kane in the back at a free-kick to send him tumbling. Kane scored and the game ended 1-1.
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The Bad-Hersfeld born defender was culpable for all three goals in the damaging 3-2 defeat against Crystal Palace at the Emirates before being part of the backline that lost 3-0 to a vibrant Leicester side a week later as the Gunners' top four hopes took a dive.
Despite Arsenal boss Unai Emery backing his man it is understood that director of football Raul Sanllehi is already discretely making it known that the German defender is available for sale in the summer at a cut price, nowhere near the staggering £35million the club paid for him.
Even with Gabriel not excelling in North London during his spell Thursday night's vital clash will again showcase his improvement since returning to Spain. Which could stand in contrast to the hugely disappointing Mustafi should he play.
All of which means Arsenal are once again on the lookout for a solid centre-half - whatever happens in the Mestalla on Thursday evening.
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