The slide showed the Republican senator’s polling numbers against Democratic challenger Amy McGrath, who lost in last month’s election.
Mr Trump used polling numbers to suggest Mr McConnell’s win against Ms McGrath was down to his support, in a Twitter post this summer.
At that point, the presentation shows the Republican’s lead over Ms McGrath widen prior to the November election.
It was sent by Mr Trump’s personal assistant on Monday, and came with a message that said: “Sadly, Mitch forgot, He was the first one off the ship!”
The remarks appeared to warn Republicans against speaking out, amid concerns that Mr Trump continues to allege the election was rigged, without basis.
Speaking in the Senate last week, Mr McConnell said he acknowledged president-elect Joe Biden as the winner over Mr Trump, as the Electoral College voted, and became the most senior Republican to do so.
“The Electoral College has spoken,” McConnell said. “So today I want to congratulate President-elect Joe Biden.”
The remarks provoked anger among Mr Trump and his allies, with the present taking to Twitter to complain.
‼️The White House is sending out this email to some congressional offices, where Trump appears to be taking credit for boosting Senate Majority Leader McConnell in his race ag. McGrath through endorsements.
“Sadly, Mitch forgot. He was the first one off the ship!” it reads. pic.twitter.com/KOndjaEYz4
— Olivia Beavers (@Olivia_Beavers) December 22, 2020
“Mitch, 75,000,000 VOTES, a record for a sitting President (by a lot),” tweeted Mr Trump last Wednesday. “Too soon to give up. Republican Party must finally learn to fight. People are angry!”
Mr McConnell reportedly warned Republican lawmakers not to back the president’s wishes to overturn the election, when Congress votes to confirm Mr Biden as president-elect next month, in another move that side-stepped the president.
Speaking on Tuesday night, Mr McConnell implored Mr Trump not to move ahead with plans to veto a military spending and policy bill approved by Congress, amid demands to revoke unrelated legal protections for social media companies.
The Republican senate leader has set aside 29 December for a vote, in the event Mr Trump does veto the bill, according to Fox News.