Because of that re-election, McConnell won't face the Republican voters again for another six years, so the threat from the former president will do little to cower the shrewd political veteran, who some political commentators have argued will now work to limit Trump's influence over the party.
In a vicious attack laced with ingratitude, Trump accused Senate Minority Leader Mitch McConnell of "lack of political insight, wisdom, skill, and personality", just days after Senate Republicans- under McConnell's leadership - thwarted Democrats' effort to convict him on the impeachment charge that he incited the deadly January 6 Capitol riot.
"The Republican Party can never again be respected or strong with political "leaders" like Senator Mitch McConnell at its helm", Trump said in a statement.
Clearly angry in his speech on the Senate floor, he said Trump's actions around the time of the attack on Congress were "a disgraceful, disgraceful dereliction of duty". "Hanging his flags. And screaming their loyalty to him", Mr McConnell said.
McConnell had remained loyal to Trump during almost all of his four years in office, when the pair were the two most powerful members of the Republican Party.
"My only regret is that McConnell "begged" for my strong support and endorsement before the great people of Kentucky in the 2020 election, and I gave it to him", Trump said.
"I single-handedly saved at least 12 Senate seats", Mr Trump claimed, "and then came the Georgia disaster, where we should have won both US Senate seats, but McConnell matched the Democrat offer of $2,000 stimulus checks with $600".
"Without my endorsement, McConnell would have lost, and lost badly".
Republican Senate leader Leader Mitch McConnell.
Trump and McConnell parted ways in the weeks after the November 3 presidential election, with Trump irked that McConnell had recognized Democrat Joe Biden as the victor.
"McConnell has no credibility on China because of his family's substantial Chinese business holdings", Mr Trump wrote.
The deeply personal attack follows McConnell's speech over over the weekend saying that Trump was responsible for the deadly insurrection at the Capitol on January 6. This number is the same as the amount of Republicans who wanted to show support to the defeated leader back in November.
But he used the blast against Mr McConnell to assert his continuing claim to leadership of the Republican party.
"If Republican Senators are going to stay with him, they will not win again", he said. He also said McConnell "begged" for his endorsement in the senator's home state of Kentucky while running for reelection previous year _ and suggested he'd work to defeat McConnell and his Republican allies, saying he planned to "back primary rivals who espouse Making America Great".
"This is a big moment for our country, and we can not let it pass by using third rate "leaders" to dictate our future!"
Asked about McConnell's reported comments that he could unite his party around opposition to the bill, Biden said: "It may unify Republicans but it will hurt America badly".