As part of an effort to manage expectations for the first presidential debate, Hillary Clinton's campaign suggested on Sunday that foul play will give Donald Trump an unfair advantage over the former secretary of state.

Senior aides to Clinton have repeatedly suggested that the Democratic nominee could be treated unfairly during Monday's debate by not receiving ample time to fact-check her Republican opponent, who has a tendency to repeat debunked claims, or facing a moderator who lets Trump's falsehoods "go unchallenged."

Clinton's campaign manager, Robby Mook, tried to set further expectations on Sunday, claiming that Trump will enjoy the advantage of being "graded on a curve" for his debate performance by members of the media and viewers.

"I'm very concerned that Trump will be graded on a curve. Just because he doesn't fly off the handle in the middle of this debate does not mean he is prepared to be president of the United States," Mook told CNN's Jake Tapper.

Mook's latest contribution to the expectations-setting game was in response to David Axelrod, a former senior strategist to President Obama and top Clinton ally, who recently said the candidate could face a "trap door" if Trump "finds a way to normalize himself" during the 90-minute debate.

Axelrod's assessment came earlier in the week as Clinton, who has kept a light campaign schedule as of late, faced tightening national poll numbers and continued to lose ground to Trump in several battleground states. The former secretary of state has also been deluged with questions about her health since she was diagnosed with pneumonia earlier this month and has failed to reverse voters' negative perceptions about her ability to tell the truth and be trusted.

Clinton's campaign has said she's likely to face tough questions about issues that have contributed to her negative ratings on honesty, mainly her email scandal and growing concerns about pay-to-play practices at the Clinton Foundation. Even before Monday's debate, her aides claimed she's likely to be pressed hard on such topics while Trump receives "one-dimensional, simple questions" from the moderator.

Despite suggesting that Trump will be "graded on a curve" at the first debate, Clinton's campaign chief simultaneously said that unless her Republican opponent "tells the truth... [and] shows his ability to conduct himself without lying constantly, he is not getting a passing grade on this debate."

"He needs to have coherent answers to the questions, he needs to demonstrate a command of the issues and he needs to roll out specific plans about how he's going to make life better for Americans," Mook said.

The first debate is set to take place at Hofstra University on Monday. It will be moderated by NBC's Lester Holt.