Joao Felix appeared to take a swipe at Atletico Madrid head coach Diego Simeone by stating conditions with Portugal are more "favourable" than with the LaLiga giants.
The Atleti forward has been linked with a move away from the Wanda Metropolitano, with Los Rojiblancos chief executive Gil Marin believing a January exit is "reasonable" to expect.
Joao Felix has scored 33 goals for Atleti since arriving from Benfica for €126million in 2019 - a tally only bettered by Luis Suarez (34) during that span.
But the 23-year-old has a frosty relationship with Simeone, with the pair reportedly falling out earlier this season.
And he appeared to aim a dig at his club boss after Portugal booked their World Cup quarter-final place with a comprehensive 6-1 rout of Switzerland on Tuesday.
"The way you play here and at the club are different," he said. "When the conditions are favourable, things go better."
Joao Felix set up two of Goncalo Ramos' three goals against the Swiss, becoming the third Portugal player to provide two assists in a World Cup game after Jose Torres - against Brazil in 1966 - and Bruno Fernandes - versus Ghana in this tournament.
He saluted Portugal's most impressive performance so far in Qatar, where he feels confidence and concentration levels are high in Fernando Santos' side ahead of facing Morocco in the last eight.
"The preparation was the same as the other games," he added. "We saw what was best and worst and played because of that, not losing our identity. We played a great game, perhaps the best so far.
"We are focused and believe completely in us. I hope it's been shown that we have a great team, we know what we want. We have the support of everyone, and won't be held back."