Maybe it was the drama of having seen his team equalise in the 89th minute and win the game just 10 minutes before the end of extra time, or perhaps it was just that the enormity of his achievement had finally dawned on Pep Guardiola.
Barcelona winning the World Club Championship was too much for the 38-year-old coach and he broke down in tears in the centre-circle as his team waited to lift their sixth straight trophy in his first full year as their manager. It was a gamble to allow a coach with no top-flight experience take over from Frank Rijkaard 18 months ago: he has repaid them by making history.
Guardiola told his players before their 2-1 win over Estudiantes: "If you lose the game you will still be the best team in the world, but if you win you will become immortals." With the 2-1 victory they became first team ever to win every competition entered in one season.
"It will be a long time before anyone repeats it, and it will never be bettered", said Gerard Pique of the 100 per cent record. "They have played like amateurs in the best possible sense of the word because they have played just for the joy of playing," said Guardiola, once he had regained his composure.
"Maybe there will be a dip now but we will fight to make sure that is not the case. Talent they already have, so we just have to keep working hard," added the coach, who will negotiate a new contract at the end of the season after a new club president has been elected.
Lionel Messi got the winner in extra time, sticking out his chest to connect with Daniel Alves's cross from the right. The former Seville full-back has now played in 11 finals and won them all. As a big-name signing, he remains in the minority at Barcelona.
Eight of the players used on Saturday were products of Barça's youth system and it was one of those, Pedro, who equalised on 89 minutes of normal time to set the stage for Messi's chested winner and Guardiola's tears.
Real Madrid hit Zaragoza for six to close the gap on Barça to just two points. Cristiano Ronaldo scored his seventh goal of the season and Gonazalo Higuian moved into double figures with a brace.
Everybody is talking about... Lionel Messi
He will be announced as Fifa World Player of the Year today. The Argentine is expected to beat team-mate Xavi and Cristiano Ronaldo to the prize. He won best player of the world club championship in Abu Dhabi and donated the €22,000 [£19,500] prize money to La Masia – the club's legendary youth academy.
Player of the week... Toni Kroos
Bayern Munich continued their recovery with a 5-2 win over Hertha Berlin but it's one of their own that is helping to keep them off the top of the Bundesliga. The midfielder Toni Kroos is on loan at Bayer Leverkusen and his two goals helped the leaders beat Borussia Mönchengladbach 3-2. The 19-year-old has now scored six goals in the side's nine wins and eight draws this season.Reuse content