Marquez is the runaway series leader, 77 points clear of Repsol Honda team-mate Dani Pedrosa, having won all nine races in the world championship season.
The 21-year-old's victory at the German Grand Prix last month saw him surpass Mike Hailwood as the youngest rider to win nine consecutive races.
Marquez is now aiming to become the first rider since Australian Mick Doohan to win 10 races in a row, something Yamaha's six-time world champion Rossi wants to prevent at this weekend's Indianapolis MotoGP.
"For Marc it is positive, for us a little bit less," said Rossi, who has finished second behind Marquez on four occasions in 2014 to sit third in the standings with 141 points.
"We have to try to beat him before the end of the championship for sure. It is a big domination, he's done great work, but in some way we have to try to beat him - for us and for the championship."
Rossi's comments were echoed by Nicky Hayden, who has failed to finish on the podium this season.
"Every so often someone comes along and resets the bar. I agree with Valentino - of course it's great what he's doing, but for us we don't want to see one guy win every race because truthfully he's making it look too easy," he said.
"It's not really the case, so I hope somebody can beat him soon. Make us look at little better."