In searing heat at the Pasadena Rose Bowl east of Los Angeles, PSG proved too hot to handle for their Spanish opponents in an impressive opening Group B win.

Goals from Fabian Ruiz, Vitinha, Senny Mayulu and Lee Kang-In sealed the three points for PSG, who delighted a crowd of 80,619 with their adventurous attacking play in temperatures that reached 31 degrees Celsius (87.8 Fahrenheit) shortly after kick-off at midday local time.

"We did very very well in difficult conditions," PSG goalscorer Vitinha said. "It was a good victory to start the competition."

PSG coach Luis Enrique said the heat "had an impact on the game."

"The rhythm of our play was a bit lower than usual, but we were better," Enrique said. "We trained at such a high level; this team loves to compete and we are ready to go as far as possible."

Atletico coach Diego Simeone refused to blame the heat for his team's struggles.

"I cannot blame it on the heat -- we both played in the same weather conditions," Simeone said. "They played much better than we did. They have amazing players and that's why they've just won everything.

"We played better in the second half. But Paris Saint-Germain is a wonderful team and they played a wonderful game."

The French giants picked up where they had left off in their 5-0 Champions League final mauling of Inter Milan a fortnight earlier, quickly settling into their smooth passing game to control the early exchanges before taking the lead in the 19th minute.

A lovely passing move down the right saw the ball swiftly transferred to Georgian winger Khvicha Kvaratskhelia who deftly laid off into the path of Ruiz to sweep in a low finish for 1-0.

With Atletico struggling to gain any kind of a foothold in the contest, the Spanish side's frustration began to show.

Clement Lenglet was booked for a rash challenge on Moroccan international Achraf Hakimi in the 21st minute, and Robin Le Normand picked up Atletico's second yellow soon afterwards for bringing down Ruiz.

- Disallowed goal -

Ruiz himself was booked on 28 minutes for a shove on Giuliano Simeone before the Argentine midfielder collected Atletico's third yellow soon afterwards.

With the Parisians in complete control, Atletico had to wait until the stroke of half-time before their first shot on goal, France's Antoine Griezmann drawing a smart save from Italy international Gianluigi Donnarumma with a low shot.

From the ensuing counter-attack, however, Atletico found themselves 2-0 down.

The electric Kvaratskhelia again found space down the left and fed inside to Vitinha, who ghosted into the box before steering a crisp shot beyond Jan Oblak for 2-0.

Atletico appeared to have hauled themselves back into the game early in the second half when Julian Alvarez rifled home a low finish to make it 2-1.

But the goal was chalked off after VAR spotted a bodycheck by Argentine midfielder Rodrigo De Paul on Desire Doue in the build-up.

That effort appeared to buoy Atletico for the remainder of the half, but despite playing with greater intensity they were unable to create a single shot on goal.

Lenglet was dismissed after picking up a second yellow card on 78 minutes.

A disappointing Atleti display was summed up by a glaring miss four minutes later, substitute Alexander Sorloth somehow scooping over an open goal from a few yards out after Marcos Llorente's cross.

PSG swiftly made Atleti pay for that miss, substitute Senny Mayulu pouncing on a loose ball to make it 3-0 in the 87th minute. The rout was completed in injury time when Lee stepped up to convert a penalty after a handball by Le Normand.

PSG will face Brazil's Botafogo in their next group match in Pasadena on Thursday, before completing the first round against Major League Soccer's Seattle Sounders on June 23.