Just short of 19 years ago, they played over an hour together as Liverpool produced one of the greatest comebacks of all time on the grandest stage of them all.
Didi Hamann's introduction at half time of the famous Champions League penalty shootout win over AC Milan in 2005 is probably one of the greatest substitutions of all time. Liverpool went to a back three at 3-0 down, the German partnering Xabi Alonso in central midfield, Steven Gerrard just in front.
They can't have known at around 10:30pm local time in Istanbul what would happen over the next couple of hours. The comeback that would be made, the bonds and memories that would remain for life.
'It couldn't have happened to a nicer guy,' Hamann told Mail Sport in an exclusive interview on behalf of freebets.com, as he discussed Alonso's success with Bayer Leverkusen this season. 'Very, very likeable, an absolute team player, quiet, good sense of humour, just a nice guy.'
It really has been quite the season for Alonso. Having taken over his side, now one of Europe's best, in the relegation zone of the Bundesliga last season, they are now staring right into the eyes of an invincible campaign.
Xabi Alonso (pictured) was right to reject Liverpool and Bayern Munich, claims Didi Hamann
Hamann (pictured) referenced the difficulty of following in the footsteps of Jurgen Klopp at Liverpool and the off-field problems at Bayern Munich
Hamann (second row, middle) and Alonso (up and right of trophy) won the 2005 Champions League together at Liverpool
'He came to Liverpool as a young kid, found his way within the team, within the club, and obviously showed a lot of people within a short space of time what a good footballer he was,' Hamann continues.
'What he's done in Leverkusen now is exceptional. I'm delighted for him, because he's been a brilliant player, but probably an even better person.'
Leverkusen wrapped up their first-ever Bundesliga title last weekend, the first side to stop German giants Bayern Munich winning the title for 12 years. They are in the semi-finals of the Europa League and heavy favourites to win that, and it seems just a formality that they will lift the German Cup too when they face Kaiserslautern in around a month's time.
44 games, zero defeats. That's their record so far this campaign. Scroll back through the Bundesliga archives and you will find that no team has ever gone a league season unbeaten. Alonso and Co might be about to make even more history.
They have ridden their luck. A 97th-minute equaliser from Josip Stanisic saved them against Borussia Dortmund at the weekend, and Jeremie Frimpong struck late at the London Stadium last week to salvage a draw against West Ham and make sure they were still yet to fail in any competition.
'Obviously they've got a huge belief,' Hamann says. 'Even if it goes to injury time and they're behind, they still believe they can get an equaliser or even win the game. I think they've done it now seven or eight times, even in 2024, not even counting before the turn of the year.
'They have very good players who stand up when when the going gets tough, and I think you need a slice of luck as well. But you've got to give it to them. It's end of April now, they're still unbeaten - what an achievement. It's exceptional, it's unbelievable, and it's very hard to put into words when they've done this season so far.'
Europe's top clubs were set to queue up for Alonso's services this summer. The hottest young coach in the world would be at the top of everyone's wish list. Liverpool, Bayern Munich, potentially even Real Madrid.
The rest of the football world waited to who it would be, but few stopped to consider that he may choose to stay put. Start a lower-rated club, taste success, then join the big time as soon as possible. That's normally the way. But not for Alonso, who pledged his loyalty to Leverkusen.
Hamann said he is 'delighted' for his former team-mate because he is 'a brilliant player, but probably an even better person'
Alonso took Bayer Leverkusen to their first-ever Bundesliga title - here, he poses with a mock league trophy
His side are also unbeaten in 44 games this season and are looking to go invincible in the campaign
It's another year of learning for him, but now learning at the top. Learning to defend his title, compete in the Champions League, how to be the one everyone else is chasing.
'I think he's made the right call,' Hamann says of the man he played alongside 38 times at Liverpool, their paths crossing before the German, eight years Alonso's senior, left the club for Bolton and then Manchester City. 'He doesn't have to prove anything.
'He's been at Bayern Munich, he's been at Liverpool, he's been at Real Madrid. As a player, he's won everything. So it's not like he's not had it. And I think he's made the the only call and the right call, because to follow Jurgen Klopp is not without danger. We've seen what happened at Arsenal and Manchester United when Arsene Wenger and Sir Alex Ferguson left - I think that it's an impossible task to follow a manager who's been as successful and as loved as Klopp.
'Bayern Munich, there are a lot of problems within the club at the moment, and he's got a brilliant team. He's got the best team in Germany. He's got a chance to win the Europa League as well, and, if they stay together - which I think they will pretty much, bar one or two players - I think he's got a great chance to go well in the Champions League next season.
'He's won the league once. Obviously they want to defend the title. Bayern Munich losing the title, it was obvious it would eventually happen. But if they lose it to a team that follows it up, that will be a statement. And also in the Champions League, I think he's a he's a guy who's obviously won the Champions League multiple times, who's got a great record there... I think that's a pinnacle for a manager to win the Champions league, and that's obviously what he wants to do..
It remains unclear what's next. Liverpool and Bayern, the two front-runners had he chosen to move this summer, need managers now. And a lot can can change in football in a year, if it is next summer that the Spaniard looks to jump ship.
Alonso has chosen to stay in Germany with Leverkusen for at least another year following his success this season
Having won the league title, they are also hoping to lift the German Cup and the Europa League
There are potentially nine games left for Alonso and Leverkusen this season. They face third-place Stuttgart this weekend in the Bundesliga in potentially their toughest test remaining, before the first of two legs against Roma in the semi-finals of the Europa League in midweek.
A decision over where Alonso heads next is a long way away. The interest in his services, however, may never dwindle, and the queue will surely be one of the longest a manager has had in 12 months' time.
'There's a chance he stays for one more season and then it depends what he wants to do,' Hamann adds, his smile as wide as the start of the conversation. 'But with his connection to to the big three clubs, I think it's very hard to see him at Manchester United or Chelsea, for example.
'If he were to go to England, I can only really see him at Liverpool. I'd be surprised if it wasn't any of the three clubs he played for; Madrid, Munich, Liverpool. I think Carlo Ancelotti might leave next season and the other two might have managers. So, it might put Madrid in the driving seat. But that can change as well.'