CNN came in second with 1.735 million total viewers and 729,000 in the demographic.
The NBA playoffs made TNT the week's most popular cable network. With both sets of stats, the arrow is more pointed at MSNBC for being a big victor here, rather than for Fox News being a loser, particularly since Fox is still on top both in overall May primetime and in all-day stats.
While left-leaning news organisations have also been accused of distorting the truth when it comes to President Trump, it is Fox News now taking the majority of heat for completely ignoring aspects of the continually developing story in the White House. Simultaneously, Fox News Channel posted its first five-day streak at No. 3 in primetime since 2000.
Over time, Fox News will learn if last week's third-place finish is a bump in the road after shuffling its prime-time lineup or a shift in the cable news landscape where it has been the perennial ratings leader since 2002.
"I do cable news in kind of a weird way, and we haven't changed the way we do the show at all", Maddow said.
For the week of May 15-19, Fox News averaged just 497,000 viewers in the advertiser-coveted key demo of adults 25-54 during primetime hours, compared to CNN's 589,00 and MSNBC's 611,000, according to the Hollywood Reporter, which cited data from ratings tracker Nielsen. If that's the case, then a smoother week might produce a return to previous form, and the normal Fox domination of prime time in both the overall and the key demo. The channel's viewership during Ms Kelly's old 9pm slot actually soared shortly after Mr Carlson replaced her, and held steady in the 8pm hour after Mr Carlson switched to that time to fill in for Mr O'Reilly.
Some believe that Fox News and President Trump friendly surrogates like Hannity are doing a poor job covering the near daily scandals erupting around the Trump White House.
Most notably, Rachel Maddow - loved by fans and loathed by detractors - has seen a steady ratings increase and is now dominating the 9 p.m. slot, occupied by "The Five" on Fox. Added CNN's Brian Stelter, "This is an extraordinary moment in the cable news race".