Lionel Messi rounded off a night of celebration with his 800th professional goal as Argentina beat Panama 2-0 in their first match since winning the World Cup.Messi, 35, claimed his 99th international goal from a free-kick after 89 minutes, sending the 83,000 fans at the Monumental de Nunez Stadium in Buenos Aires into raptures.Substitute Thiago Almada had grabbed the opener 11 minutes earlier after a Messi free-kick had come back off the post.Manager Lionel Scaloni named the same starting line-up as the World Cup final with the entire squad from Qatar posing for pictures in front of a replica trophy before kick-off.But they were made to wait for the breakthrough as Panama goalkeeper Jose Guerra produced several saves and the defence fought valiantly to keep out the World Cup champions.Argentina face Curacao on Tuesday to round off a week which has seen Messi widely celebrated as a hero.Cristiano Ronaldo became the first and only other player to reach 800 officially recognised career goals, in November 2022, and has since reached the 830 mark.Ronaldo scored two in Portugal's 4-0 win over Liechtenstein last night, taking his international tally to 120 in what was a world record 197th cap.