The side were among the pre-tournament favourites, but struggled to get out of their group before falling to France in the Round of 16.
“The best player in the world was devoted” to the Argentina cause, Sampaoli told Marca.
The former Sevilla manager pointed out the difference between the environment Messi has at his club, which enables him to thrive, and the one the Argentina talisman faces within the national setup.
“At his club (Barcelona) he has great stability. But when he comes to the national team a collective hysteria takes over and it’s like we’re expected to win.
“This is not possible. If we don’t win, it’s he who cops all the criticism. So you can’t play, and you can’t enjoy it.”
“The weight of expectation on this team was too heavy. We all felt pushed by the obligation to win, which meant it was difficult for us to express our talents.
“It was difficult to work in those conditions because there was only one available option: to be world champions.
“Putting that kind of obligation ahead of the match itself made everything much more complicated.”
Sampaoli also had words of advice for his successor in the Argentina hot seat, Lionel Scaloni: “We need to find a balance so that this obligation to win doesn’t generate even more anxiety.
“Every match (at the World Cup) was a sufferance.”
Meanwhile, Messi’s international future remains unclear. He made himself unavailable after the World Cup, missing Argentina’s friendlies last month as well as the upcoming international break, though he has not officially retired.
Diego Maradona has yet again slammed the Argentina national team set-up, saying the country’s football association is full of “traitors” and criticising midfielder Javier Mascherano as he continued his robust defence of talisman Lionel Messi.
Messi informed the Argentinian FA (AFA) that he would not be available for selection for the foreseeable future, missing the team’s friendlies in September and again not being named to the squad for the upcoming international break. However, he has not officially retired.
Maradona led La Albiceleste to their last World Cup win in 1986 and managed Messi and many more of today’s stars, including Mascherano, during a short stint that included the 2010 World Cup.
He believes Messi – his successor as the country’s great footballing hope – owes the national team no more, and should not come back for international duty again, after the criticism he has received for not winning a trophy with the national side during an otherwise decorated career.
“That’s why I am telling him not to come back and take all of the blame,” said Maradona of Messi.
“We will mourn him because there is no other player like him, but just as Messi falls, so does the AFA.
“It is very easy to say that Messi is to blame, but they are going to kill the kid.
“And this kills me because if there are comrades who really love Messi, they should have come out and defended him, not press silence.
“I was wrong about Mascherano, I thought he was a leader. Today, I have to say that Mascherano is not what I believed, but that mistake is totally mine, not his.”
The Argentina legend, who is now manager at Mexican side Dorados, also ruled out a return to the national team job.
“I won’t return,” said Maradona.
“I’m really looking forward to doing a lot of things here and in the national team there are a whole bunch of traitors, so I’m not going back.
“We wanted a new AFA and we got [Claudio] Tapia. I’m guilty in that as well. He came to ask for support and I said yes.
“He told me a lot of things and then did nothing, he did not call me anymore. That’s betrayal and I spit in the face of traitors.”
Here Press Association Sport takes a look at some of the numbers behind the extraordinary career of the Argentina star.
22 – Messi has scored 22 goals against English clubs in his career – more than against clubs from any other country outside of Spain. Arsenal have come off worst, with Messi scoring nine times against the Gunners, while he has also scored six against Manchester City.
8 – Messi scored a record-breaking eighth Champions League hat-trick of his career in the 4-0 win over PSV last month. His feat lifted him clear of his long-time rival Cristiano Ronaldo, who has scored seven.
562 – Messi’s brace against Spurs took him to 562 at all levels for Barca, according to the player’s official website.
4 – Messi has won four Champions League titles with Barcelona. But recent dominance of the competition by rivals Real Madrid has seen him fail to get his hands on the famous trophy since 2015.
128 – Number of Argentina caps won by Messi, whose international career has not mirrored the success achieved with Barcelona. Olympic gold in 2008 notwithstanding, Messi is still yet to lead his country to a major title – and on the evidence of this summer’s World Cup, he may have some time to wait.
100,000,000 – The number of euros which reportedly make up Messi’s basic annual salary, having signed a new deal with Barcelona in January. If correct, the figures make Messi the world’s highest-paid footballer, and the first whose calendar earnings breach the nine-figure barrier.