This is the biggest night for Los Angeles college hoops in … I think it is safe to say “forever.”

Both USC and UCLA have battled into the quarterfinals of the NCAA Tournament. That has never before happened.

And not only that, they are playing in the same city tonight, in the same arena, one after the other, and if both win they will meet each other in the Final Four, with one or the other winning a championship next week, on April 3.

This is mind-boggling, considering how erratic both programs have become, but they have been outstanding this month, and a bit lucky, and SoCal people from all over the world will be hoping to tune in — even if the first game starts at 1:15 a.m. here in France.

UCLA has made lots and lots of runs deep into the NCAA Tournament, (see: John Wooden), but none since 2008, when Jim Howland took the Bruins to the Final Four in three consecutive seasons.

USC basketball has had a few moments, over the past century, with one Final Four appearance, in 1954 (not even I remember that), and an Elite Eight appearance in 2001.

The idea that they could play each other in the Saturday semifinals … my head is about to explode.

Each team has a lot of work to do. Each is an underdog. USC by nine points, UCLA by 6.5.

In the first game, USC gets No. 1-ranked Gonzaga, which is 29-0 and three victories from becoming the first team since Indiana, in 1976, to finish a season unbeaten.

Gonzaga, a Catholic school located in Spokane, Wash., not that long ago was considered the epitome of “mid-major” programs. Now, the Zags want it all.

They have a bunch of very good players, and are well-coached and it seems likely generic fans would like to see Gonzaga run over the Trojans.

In part, because USC is a former national football power, and USC haters would prefer to see them lose every game in every sport until they have their generic cardinal-and-gold arrogance beaten out of them.

But they have a very nice team in hoops, led by a guy named Andy Enfield, who took Florida Gulf Coast, a 15 seed, to the Sweet Sixteen in 2013. Only time that has been done, and USC noticed.

Enfield got USC squared away, and this year’s team now is 25-7 and boasts a pair of brothers who are very good — Evan and Isaiah Mobley, and the former is considered a potential No. 1 pick in the NBA draft.

The Trojans have pretty much rolled through their three tournament games, and neutral observers are suggesting they could give Gonzaga trouble.

The game will start at 6:45 p.m. (PDT), in Indianapolis.

Following at about 10 p.m. (PDT) … which is 4 a.m. in France … are the Bruins versus Michigan.

UCLA may be the biggest surprise of this tournament.

They got into the the bracket by something rather like unlocked door, as a fairly disappointing, 17-9 “First Four” team, having to play a game just to get into the 64-team main bracket. Sort of embarrassing, having to do that, with those 11 NCAA titles on the Bruins’ resume, but they beat Michigan State in First Four overtime, then knocked off BYU, Abilene Christian, and second seed Alabama, 89-78, also in overtime.

The Bruins are led by Mick Cronin, a no-nonsense guy whose season went from “disappointing” to “well done” in the span of a couple weeks.

Michigan is a tough matchup because it has more big men than any dozen circuses, and they hang around the rim waiting for smaller folk to come by.

UCLA has been very good on defense and making three-pointers, and they may not be quite as good as USC, but Michigan isn’t as tough as Gonzaga.

UCLA has been trying to get back to elite-every-year status — there have been 10 coaches since John Wooden retired — and those 10 guys managed exactly one NCAA title to add to the 10 Wooden’s teams won. (Jim Harrick’s 1995 team led by the O’Bannon Brothers. Hmm. Brothers …)

Anyway, this is about as good as it gets, for L.A. college hoops. Don’t miss it. It comes around less often than Halley’s Comet.