We have a late contender for song of the year: It’s called “Love Fight,†and it’s a “shuffle in C, four on the floor, just stay on the rhythm and you can’t go wrong,†if that means anything to you. In the loosest, most joyful sketch of last night’s Saturday Night Live, Kristen Wiig is an army nurse and Bowen Yang is a tough troop performing for their unit’s Christmas Eve USO Show in 1944. But don’t let their transatlantic patter fool you, because “Boogie Woogie Bugle Boy†this ain’t. The duo performs a gender-swapped R&B duet about a player sleeping around on his girl, the kind that has dramatic spoken-word interludes acted out on cell phones. By the second verse, Bowen is grinding on Kristen and the old-timey troops are totally into it. And for a third-act surprise, Dua Lipa enters to play the role of the other woman, aka “Maaaarjoriiie.†The only way Kristen can make it up to her women? Why, defeat the Nazis, of course.