Almost eighteen years on from making his senior debut for Real Sociedad in December 1999, Xabi Alonso is one game away from retirement.

Bayern Munich face SC Freiburg at the Allianz Arena on Saturday in what marks the Spaniard's last ever game as a professional footballer - and what a career he's had.

Not only has he played for three of the world's biggest clubs in Liverpool, Real Madrid and Bayern, but his list of achievements is never-ending.

It reads as follows: 1x FA Cup, 2x Champions League, 1x La Liga, 2x Copa del Rey, 3x Bundesliga and 1x DFB Pokal.

And that's without mentioning Alonso's success on the international stage with Spain, winning the 2010 World Cup and the European Championship twice in 2008 and 2012.

Simply put, the midfield maestro will retire as a legend of the game.

With retirement comes reflection and heading into his final game, Alonso has recalled how he felt when he made his Premier League debut against Bolton Wanderers in 2004.

Liverpool lost 1-0 at the Reebok Stadium that day, where Alonso demonstrated his range of passing but took a battering from Bolton's players.

"I remember [after] 15, 20 minutes I think it was a Kevin Nolan tackle, a 'welcome to the Premier League tackle,'" he told the Times.

"Then there was [Jussi] Jaaskelainen from his kicks, not even trying to pass, just long balls up to Kevin Davies.

"I said to myself, 'This is different. OK, Xabi, you want to make it here, become a pro with Liverpool you need to learn fast.'"

As we know, Alonso quickly adapted to life on Merseyside and marked his first season by memorably winning the Champions League.

But despite achieving so much throughout his illustrious career, the former Spain international claims he has three regrets.

"Maybe I have three," he added. "With Real Sociedad, my club, we were one game from winning La Liga [in 2002-03].

"With Liverpool we were so close to the Premier League. With Bayern, so close to the Champions League.

"But maybe that would be too much to ask, too perfect. If you can call them regrets... but that's just football. When I look back, I can be happy that I've done what I wanted, dictated my path."

In his five years at Liverpool, the closest Alonso came to winning the Premier League was in his final season, where they finished second and four points behind Manchester United.

It comes as no real surprise that the following season, after Alonso moved to the Spanish capital, Liverpool finished seventh. How he has been missed.