In the following season, Katsouranis made three appearances in the Intertoto Cup, scoring one goal as Panachaiki finished fourth out of five in their group.

Fernando Santos however, Panathinaikos' coach at the time, decided to sign Portuguese Carlos Chaínho, a player he knew when at Porto, which meant Katsouranis' transfer would not be finalized.

In his first season, alongside his teammate in the national team, Thodoris Zagorakis he formed an amazing "duo" in the midfield of AEK.

[4] In fact, he had an excellent performance in the UEFA Champions League group stage matches of that season and also scored a historic goal against Real Madrid at the Santiago Bernabéu Stadium.

[6] In the summer of 2004, Katsouranis remained at AEK, despite several offers, having agreed a new three-year contract, while most of his teammates from the previous campaign had acted on their frustration and left.

Werder Bremen expressed strong interest for the Greek international, but both Katsouranis and Nikolaidis decided to reject the offer.

[8] Despite radical changes to the squad in the first season under Nikolaidis, players, fans and club staff came together to create an electrified atmosphere at every AEK game.

Led by captain Katsouranis, the team responded with great performances, only missing the championship on the final day of the campaign.

[9] Katsouranis signed a four-year contract with Portuguese club Benfica on 22 June 2006, joining his former manager Fernando Santos and his teammate with Greece, Giorgos Karagounis.

[13] In October 2012, Panathinaikos president Giannis Alafouzos terminated his contract with the club, with Katsouranis paying the price for team's bad performances at the start of the 2012–13 season.

[14] Katsouranis has been serving a six-match suspension for verbally abusing a referee in a Greek Super League match in August.

Alafouzos reportedly told the rest of the squad that the player was "history" at Panathinaikos, whilst also expressing his displeasure about "two or three other(s)", without going into specifics.

[15] Katsouranis left Panathinaikos with rumours for a lot of problems with foreign players and the accusation of controlling the changing rooms.

It formed part of the policy of the new PAOK owner, Ivan Savvidis, who insisted on the acquisition of Greek internationals in order to boost both the strength of the roster and the prestige of the club.

He formed a strong partnership with Gordon Schildenfeld in the defence reducing to a great extent the goals which PAOK conceded.

He believed that PAOK needed time and patience to identify changes to a club that really tries to make a break with problematic situations and detach from stereotypical stories.

It was a tremendous game as the fans then use the pitch as a giant ashtray by throwing their flares onto the grass and set fire to one of the dug outs.

Apart from being a great player, he is an amazing human being his passion for football, down to earth personality and desire to learn and share sets him apart.

One of them, Katsouranis, winner of the 2004 Euro, scored his fourth goal in the season, becoming the league's second top-scorer just beneath Brazilian international Elano.

"I will give it all for Atromitos", stated Katsouranis who in the first half of the season plied his trade in India, with remarkable success in that up and coming mini-league that lasts only a few months.

He signed for Atromitos in a six-month deal with an option for one year more, however, the Athens club decided not to keep Katsouranis in their squad ahead of next season.

On 15 September 2015, Katsouranis signed with NPL Victoria club Heidelberg United on a one-match contract, with the option to extend it should they win their following FFA Cup match.

During the 2021/22 season he started working as a commentator and analyst of the Greek Super League 1matches, in the show of the YouTube channel "Betarades".

Katsouranis made his international debut for Greece on 20 August 2003 against Sweden and scored his first goal against Kazakhstan in a 2006 FIFA World Cup qualifier.

Forced his way into the starting XI after coming off the bench for the opening game of the tournament, he was an extremely important part of a three-man midfield that also included Theodoros Zagorakis and Angelos Basinas.

[49] After the draw for UEFA Euro 2016, Katsouranis stated that he was confident of reaching the finals due to a lack of "powerhouses" in their qualifying group.

Katsouranis could play in various positions, characteristic shared with Ruud Gullit as a result of the combination of his technique, speed and strength.

However, it was his natural attacking instinct that makes him such a valuable footballer, being able to ghost into the box with regularity despite usually playing in a deep-lying midfield role.