Bernardo Viana also told Reuters the lawyers had agreed to give Formula One and the sport's governing body, the FIA, until mid-October to respond to a Letter Before Claim sent to them on August 15. The legal team had initially set a Friday deadline.
Lewis Hamilton finished second while George Russell also made the podium in Barcelona.
Red Bull have now claimed all three Grand Prix wins in the new season, a record for the team, resuming their dominance after their runaway success in 2022.
The team ended an unprecedented run of eight successive constructors' titles with third place overall last year after wrestling with a bouncing car whose performance was hard to extract.
Max Verstappen led from pole position at the Autodromo Hermanos Rodriguez, taking the chequered flag 15.186 seconds clear of Mercedes's Lewis Hamilton.
Seven times world champion Lewis Hamilton finished second.
The 24-year-old Dutch driver took his 26th career win 0.9 of a second ahead of Spaniard Sainz, who closed the gap and set up a thrilling final chase thanks to a safety car deployment.
Seven-time world champion Lewis Hamilton and the FIA were in a standoff at this month's Miami Grand Prix over piercings the Mercedes driver has raced with for years and said he could not remove.
The sport's only Black driver, an outspoken champion for equal opportunities and diversity, Hamilton has also experienced racism and online abuse.
"I don't really fully understand the whole idea when people get married the woman loses her name," said the seven-time Formula One world champion.