Marc Marquez is reigning MotoGP champion and the most dominant rider of recent years. Valentino Rossi is of one the most dominant and popular former champions in the sport's history.

Together, they have the fiercest rivalry on two wheels, with crashes, kicks and harsh words in a simmering feud that can erupt at any race.

Given their most recent dustup, three weeks ago in Argentina when the Italian Rossi called the Spaniard Marquez a "dirty" rider, the series' return to the track at the Grand Prix of the Americas in Texas could spark some new fireworks.

Other riders are starting to tire of the bickering. Australia's Jack Miller even suggested it is dangerous for others on the track.

"We are all here racing and risking our lives," Miller said. "I think it is quite silly and immature."

Rossi, 39, and Marquez, 24, have won 11 MotoGP championships between them. Rossi's last world title was in 2009 and Marquez has dominated the recent era with four championships since 2013. Their nastiest battle came in 2015 when Rossi appeared to kick Marquez in the Malaysian Grand Prix and sent him tumbling into a crash that knocked Marquez out of the race.

The kick also cost Rossi a shot at his eighth MotoGP championship and 10th in all classes as he was forced to start the final race that season from the back of the grid as a penalty; he ultimately lost the title to Jorge Lorenzo.

The kick that season was the lowlight in an already tense sprint to the finish that saw Marquez even complain that an Italian television comedy crew was harassing his family late in the season.

The feud had been somewhat dormant until Marquez's wild race in Argentina. It began with him frantically trying to restart after his motorcycle stalled on the starting grid. After disrupting the grid and ignoring orders to go to the back, Marquez was forced to ride through pit lane after the race started. He'd been heavily favored and his desperate bid to get back to the front was chaotic as Marquez first bumped Aleix Espargo and then knocked Rossi into the grass and out of the race.

Marquez, who was penalized for both incidents, blamed the touch with Rossi on wet conditions on the track and finished 18th. Rossi called Marquez a menace who is "destroying the sport" with his aggressive driving.

"It was a strange race," said Britain's Cal Crutchlow, who won the race and took the lead in the season standings. "Not only from my point of view, but what was going on behind."

Neither rider seemed interested in fanning the flames ahead of Sunday's race, at least not in their English language interviews Thursday. Rossi said he is not yet ready to meet with Marquez to hash things out. He also didn't back off is post-race comments criticizing Marquez.

"I think exactly what I said after the race in Argentina," Rossi said. "It's better to look forward."

When asked about Rossi, Marquez also decided to keep it generic.

"I'm a rider. I like to learn from everything. From that Sunday, everyone can learn and we'll try to improve for the future," Marquez said.

Marquez could tamp things down quickly if he shows the same dominant form he's had over the last several years at the Circuit of the Americas. The track built for Formula One cars has been a sweet spot for Marquez as his powerful Repsol Honda has scarcely been challenged through its s-curves and long straight. Marquez has won the Texas race the last five years with a pace that has often left Rossi well back in the distance.

Rossi's Yamaha may still make it a fight. He finished third in 2015 and second last year, a result that temporarily put him on top of the season standings. Marquez and Rossi were 1-2 in Friday's first practice session.

Everyone will be watching for new clashes this weekend. France's Johann Zarco said the feud threatens to overtake MotoGP when there is good racing throughout the grid.

"We are touching two gods, we have (Rossi) that is the first god and now Marc is becoming this other god because he is doing incredible things," Zarco said. "It is between riders that we must almost speak together and find a solution together."