As you approach the west facade of Atletico Madrid’s Metropolitano stadium, the new, outskirts-of-town arena they call home, there is a feature known as the "Paseo de las Leyendas".
Steel plaques, more than 150 of them, are tiled into the ground, one for each player to have appeared more than 100 times for the club.
When the stadium first welcomed Atletico fans at the beginning of the season, one or two of the plaques suffered a little, from stamping and scratching.
They were the ones that carried the names of footballers deemed to have turned their backs on their club, like strikers Hugo Sanchez, who joined Real Madrid in the 1980s, and Sergio Aguero, who left while still young for the riches of Manchester City. Mostly, though, the idea of a walkway of homage has been respected.
Wander through the Paseo de las Leyendas, and you are reminded of one striking feature of modern Atletico. The legends may go on elsewhere, but they very often come back.
Fernando Torres’s plaque records his two spells, the "Boy Wonder" period from 2001-07, and the emotional, fulfilling return, from 2015, which will end this summer. And there’s Gabi, enduring club captain for the twin Uefa Champions League finals of 2014 and 2016 and the Primera Liga title four seasons ago. He has two stints on his plaque.
As for Diego Costa, his plaque is crowded with dates. The striker recently played his 150th match for Atletico, his contribution to the club’s rise over the last decade spread over not one, not two, but three distinct spells.
The latest began in January and might yet deliver him an instant, first major European trophy. The Brazil-born Spain international was away from Atletico when they won the Europa League in 2010 and again in 2012.
Injury kept him out of most of the 2014 Champions League final, and when Atletico returned to that stage two years later, Costa was at Chelsea.
His return to Atletico, having fallen out very publicly with Chelsea manager Antonio Conte, has been a success. There have been goals, and, inevitably, a red card almost immediately – on his debut at the Metropolitano – but he is 90 minutes from the Europa League final and has forged a fruitful understanding with Antoine Griezmann, Atletico’s leading scorer.
They dovetail naturally, with Costa taking on something like the role he played as foil to Radamel Falcao, Aguero or David Villa in past versions of Atletico.
He makes space for his partners with his industry, he draws anxious defenders in his direction. And, to Diego Simeone, the manager who gratefully seized upon the broken relationship with Chelsea, Costa carries a flag for what Atletico do best: courage, aggression and never-say-die. “He gives so much to the team,” Simeone said. “Strength, tenacity, bravery and everything else he brings to our group.”
Simeone, delighted at Costa's swift recovery from the hamstring problem that kept him out of the side for the drawn first leg of the Europa League semi-final, knows everything the player brings to Arsenal's minds, too.
In his three seasons making enemies and winning admirers for his effectiveness with Chelsea, Costa developed an especially toxic relationship with Arsenal.
Just ask Laurent Koscielny. Koscielny was at the heart of a notorious cat-fight at Stamford Bridge, when then Arsenal defender Gabriel Paulista was sent off, with Arsene Wenger, the Arsenal manager, accusing Costa of provocation.
The provoker earned a three-match ban based on post-match review of the incidents. But he was back to inflict further damage that season on Arsenal’s title hopes when he scored the only goal of a London derby after Per Mertesacker had been sent off fouling him.
The last encounter, when Costa registered his third goal in six games against Arsenal, turned out better for Wenger’s men.
“We went to work on Costa,” said a satisfied Mertesacker after Arsenal beat Chelsea 2-1 in the FA Cup final last May.
Their niggling nemesis never played again for Chelsea, his thoughts already turned back towards Atletico, the club that has fitted him best through his turbulent career and where he is now cast once again as scowling spoilsport to Wenger and Arsenal’s aspirations.