It was only a friendly match against Jose Mourinho's Porto but it was the start of a memorising career in Catalonia, and for Argentina, that has led to some considering the Argentine as the greatest player to ever live - breaking records, amassing titles and scoring unforgettable goals along the way.
Here are 29 key moments in the career of the Blaugrana and Albiceleste's no.10:
30/03/1994: Messi signs for Newell's Old Boys and until 1999 scored 234 goals in 176 matches, averaging 1.33 goals per game.
09/04/1994: Newell's debut against Pablo VI, winning 6-0 and scoring four goals.
08/05/1998: Messi's maternal grandmother, Celia Olivera Cuccittini, dies. She was the one who encouraged him to play football and the person he dedicates his goals to.
17/09/2000: Arrives in Barcelona with his father, Jorge, to pass a trial with Barça. Carles Rexach advised the club to move immediately but the player returned to his homeland to await a response.
14/12/2000: Carles Rexach met with Josep Maria Minguella in a restaurant to sign the famous "paper napkin contract", the first contract Messi signed with the Blaugrana tieing him to the club until June 30, 2003.
16/11/2003: Debut in a friendly game between Porto and Barça at 16 years and 145 days old. Frank Rikjaard's team lost 2-0, Messi replacing Fernando Navarro after 75 minutes.
16/10/2004: Official Barça debut (17 years and 114 days old) in the Catalan derby against Espanyol. Replaced Deco in the second half.
01/05/2005: Scored his first official goal for the team against Albiceleste in game 34 of the 2004/05 season.
02/07/2005: Become under-20 champion with Argentina as the Albiceleste win the final 2-1 against Nigeria, Messi scoring twice and becoming the tournament's top goalscorer and best player.
17/08/2005: National team debut against Hungary, sent off two minutes after coming on as a substitute.
18/04/2007: Scored two goals in the Copa del Rey semi-final against Getafe, one of which was similar to that of Diego Maradona at the 1986 World Cup against England. Goes on to emulate another Maradona goal on June 9 the same year, scoring an infamous 'hand of God' in the 2-2 draw with Espanyol.
23/08/2008: Wins a gold medal with the Albiceleste at the Olympic Games in Beijing, beating Nigeria 1-0 in the final thanks to Angel Di Maria's goal.
02/05/2009: Finds the net twice in Barça's memorable 6-2 Clasico thrashing at the Estadio Santiago Bernabeu.
27/05/2009: Barça win their third European Cup and Messi scores the second in a 2-0 win over Manchester United in Rome.
01/12/2009: Wins his first Ballon d'Or, Cristiano Ronaldo came second and Xavi Hernandez third.
19/12/2009: The Blaugrana win the Club World Cup 2-1 after extra time against Estudiantes, Messi getting the decisive goal.
06/04/2010: Scores all four against Arsenal in the Champions League quarter-final second leg. At the end of the 2009/10 season he wins the Pichichi and Golden Boot.
28/05/2011: Barça beats United once again in a Champions League final, this time at Wembley and, once again, Messi scores on the biggest of stages.
27/07/2011: Named 'Patrimonio Deportivo Historico de la Humanidad' after the vote of more than 327,000 people from 72 countries.
18/12/2011: Barça triumphs over Santos 4-0 in the Club World Cup final, Messi equals Pedro Rodriguez's record of scoring in six official competitions that calendar year.
10/01/2012: Wins his third Ballon d'Or ahead of Andres Iniesta and Xavi, the first time that three players from the same club have stood on the podium together.
22/11/2015: Achieves a hat-trick in the 5-1 defeat of Sevilla, reaching 253 goals and surpassing the record of Telmo Zarra's 251 dating back to 1955.
15/02/2015: In league game no.300 (a 5-0 win against Levante), provides assist number 106 and scores another hat-trick to go above Zarra's record for a Spanish club (31) and above Cristiano Ronaldo for the most in La Liga.
06/06/2015: Wins his fourth Champions League title and Barça's fifth, defeating Juventus in the Berlin final and adding to the league and cup triumphs in the weeks previous to complete the club's second treble in its history.
11/01/2016: Fifth Ballon d'Or with 41.33 per cent of the vote ahead of Cristiano Ronaldo (27.86) and Neymar (7.86).
14/02/2016: Emulates Johan Cruyff by passing a penalty for Luis Suarez to convert in the Blaugrana's 6-1 win over Celta Vigo.
17/04/2016: Reaches 500 career appearances in the league game against Valencia (450 for Barça, 50 for Argentina).
22/05/2016: Wins the Copa del Rey against Sevilla, providing two assists. A week earlier, Barça were proclaimed league champions after beating Getafe.
19/06/2016: Surpasses Gabriel Batistuta's record of 55 goals for Argentina, scoring in the 4-0 Copa America semi-final win against the United States.