Daniel Ricciardo's smile beamed its brightest in months, while his Red Bull teammate Max Verstappen steamed.
Lewis Hamilton, meanwhile, looked completely comfortable knowing he's in a perfect spot to win his fifth career Formula One championship.
Ricciardo snatched the pole position from Verstappen at the end of a sizzling round of qualifying at the Mexican Grand Prix on Saturday, setting up a Red Bull fight from the front row as both drivers duel for the team's third win of the season.
"I knew the pace was in the car," Ricciardo said. "I've got to relax a little ... I need to save a little serenity for tomorrow."
Hamilton will start third, knowing he can let the Red Bull cars go off and running while he coasts his Mercedes to the finish line. A seventh-place finish will secure the British driver's fifth career title, matching the late Juan Manuel Fangio of Argentina for second most in F1 history. Only Germany's Michael Schumacher has more with seven.
Hamilton missed his chance to win the title last week at the U.S. Grand Prix when he finished third.
"To be as close as I am, I'm really quite happy," Hamilton said. "I'm just praying for a smooth and safe race."
The 1-2 start will be the first for Red Bull since the start of the hybrid engine era in 2014. Still, the 21-year-old Verstappen was fuming after missing his chance to be the youngest driver to earn pole position in F1 history. He lost it by 0.026 seconds.
Verstappen said his car didn't feel right despite fast times in Saturday morning practice and the early stages of qualifying.
"I felt like I couldn't push the car to its limit," Verstappen said. "I didn't feel good at all."
The Red Bulls came in expecting to be strong in the high altitude at the Autodromo Hermanos Rodriguez. Verstappen is the defending race champion and dominated the three rounds of practice.
He scorched the field again in qualifying until Ricciardo snatched his third career pole position and first since his win in Monaco in May. Verstappen was still on the track but his final lap was too slow.
Ricciardo's effort set up what could be the Australian's last best chance to win for Red Bull. He's leaving the team for Renault in 2019.
Verstappen and Ricciardo will have to decide how much to fight each other for the win. The two had a costly collision in the Azerbaijan Grand Prix that knocked both cars out of the race. Both drivers were reprimanded for dangerous racing moves and team tensions were high.
"It's too early to say it's just going to be a race between each other, as nice as that would be," Ricciardo said. "Hopefully we're in a quicker car all day."
Team principal Christian Horner wants to keep it clean.
"Our priority now has to be to try and convert these fantastic grid positions into a haul of points tomorrow," Horner said. "The team has worked very hard for this so it is crucial that we now make the most of it."
Hamilton said he'd like to go for a win to punctuate a season championship, but he doesn't give himself much of a chance to do that Sunday.
"Those guys (Red Bull) are in a league of their own," Hamilton said.
He'll want to be cautious from the start as the cars barrel through the opening long run into the first turn. It would normally be a chance for Mercedes and Ferrari to flex their straight-line power, but it also can lead to a wild start of collisions and cars bailing out in the runoff areas to avoid them.
Hamilton started third last year and a first turn bump from Ferrari's Sebastian Vettel punctured a tire. Hamilton limped to a ninth-place finish but still clinched the season championship.
Vettel starts right behind him again Sunday and must win if he has any hope of extending the championship to the next race in Brazil.
"You saw what happened last year with the red car behind me," Hamilton said. "Everyone is going to be barreling into turn one. If there's an opening and an opportunity to take it, I'll take it. If not, I'll hold position."