Red Bull Arena hosted the first-ever competitive outing for a Video Assistant Referee in professional soccer history on August 12, 2016. It was a match between New York Red Bulls II and Orlando City B in USL - the third tier of US pro soccer.

The game itself finished 5-1 to the reserve Red Bulls, thanks in part to VAR. There were two reviews in the match, both resulted in cards to Orlando players. The first saw Conor Donovan issued a straight red card for fouling NYRB II's Junior Flemmings to stop a breakaway on goal. The second saw Kyle McFadden given a yellow for a foul on Florian Valot: also significant, because McFadden would be sent off shortly thereafter for picking up his second yellow card.

So VAR did affect this match profoundly: it inspired decisions that directly led to Orlando finishing the match with nine players.

There will be at least four other games featuring VAR in USL this season: every remaining NRYB II regular season home game. We'll have quite a bit more familiarity with it by the time this experiment is over. And it is an experiment: the lessons of this experience will inform how VAR is tweaked and deployed more widely as IFAB continues its planned testing of the concept and execution.

Here's what one observer learned from the first-ever official use of video replays to assist refereeing decisions in professional soccer history:

1. It won't stop fans (or players, or coaches) from questioning calls

The first-ever VAR-inspired review in the first-ever match featuring VAR occurred in the 34th minute. Junior Flemmings was fouled. Referee Ismail Elfath called for a free kick on the edge of the box. The VAR had a whisper to the ref, and Elfath jogged over to take a look at the replay to decide...we didn't know exactly what he was looking at. Would he change the call from foul outside the box to penalty kick (Flemmings' momentum was clearly carrying him into the box)? Did Flemmings over-sell the foul and would he get a yellow for embellishment? No and no. Elfath upgraded his call from foul to red-card foul. Conor Donovan was sent off.

Here's a look at the first Video Assistant Referee call to ever happen in a live competitive soccer match! #NYvORLhttps://t.co/b8mXnsrw2o — USL (@USL) August 13, 2016

Replay or not, that is still a debatable call. Not as debatable as, say, Hilario Grajeda's litany of errors in RBNY's last match. Or the calls that marred the Olympic women's soccer quarterfinal between USA and Sweden. But still, debatable.

Even more debatable, though we lack a video clip of the incident: Elfath's second VAR-inspired decision.

Per IFAB's media briefing in late July, the only incidents the VAR is supposed to check are goals, straight red cards, penalties, and cases of mistaken identity.

So the two incidents Elfath chose to review were presumably recommendations for straight reds from the VAR - though the foul on Flemmings might conceivably have been a recommendation for a PK. The standard for VAR-intervention is "clear error", at least in the VAR's mind.

If we had a video clip of the foul on Valot - which Elfath merely called a foul - you'd be seeing a reckless tackle deemed red-card worthy by the VAR. But not by the head referee. Elfath looked at the tape again, and upgraded his original call to a yellow, not a red. That's a call already debated by VAR and center ref: of course others will debate it too.

And, of course, there will also be the very fair observation that many reviewed calls should never have required the VAR's virtual tap on the shoulder in the first place:

@Once_A_Metro Some will wonder tho, shouldn't a competent ref be able to make that call w/o assistance. — Alex S. (@Quickstrike_A) August 12, 2016

If MLS imagines VAR will bring an end to the sort of embarrassing refereeing that effectively forced the league to apologize via press release for the inadequacy of its officiating, it should think again.

VAR clearly has the potential to clear a lot of problems up. The standard suggested by IFAB Technical Director David Elleray is the Raul Ruidiaz handball that saw Peru past Brazil at Copa America Centenario. Yes, VAR should stop that sort of thing from happening. But it won't stop fans questioning referees. Far from it: with VAR in the stadium, when there are major grievances to be aired, they'll be supported by the knowledge the ref saw exactly what happened. The "ref didn't see it" excuse is off the table.

2. Referee and VAR can disagree

Already covered above, but worth repeating: the referee and VAR don't have to agree. When Ismail Elfath reviewed Kyle McFadden's challenge on Florian Valot, he was being invited by the voice in his ear to issue a red card for a tackle he'd merely called a foul. Elfath looked, and decided it was a yellow.

If the very first game ever to feature VAR can bring us an incident of the center ref watching the replay and reaching a different conclusion from the one recommended - chances are it will happen again.

3. The process can be quick

Per the match video's game clock, Junior Flemmings was pulled down at around the 33:42 mark of the first half. The players, as they are wont to do, ate up time with their own antics. Flemmings rolled around a bit, the other NYRB II players looked for Elfath's instruction on where to line up the kick; OCSC's Conor Donovan appeared to take a moment to argue that Flemmings had taken a dive. Elfath signaled for the replay almost exactly a minute after the original foul - at the 34:42 mark of the match.

He announced his departure from the field to watch the video. Jogged off. And was back on very shortly. Donovan was running off the field with a red card brandished behind him by the 35:12 mark of the match.

All told that's about 90 seconds from foul to VAR-adjusted decision. And at no time did the VAR interruption feel like it was holding up the game. Players often dither and argue for longer when a call hasn't gone their way. The free kick itself was taken at around the 36:00 mark. So a total of two minutes and 18 seconds elapsed between foul and free kick. Not unreasonable for a red card foul, with or without VAR intervention.

Join the video below at the 42:44 mark to see for yourself.

4. The process can seem interminable

Now scroll that video forward to 1:43:22. At the 79:07 mark on the game clock, Kyle McFadden takes a clumsy touch trying to work the ball out of the Orlando defensive third. He hurries to prevent Florian Valot from winning possession, and leaves the NYRB II player in a heap.

In truth, the VAR process doesn't seem to take much longer than the first time Elfath heeded the voice in his ear. By around 81:38 on the game clock, he's back on the field. He's issued the yellow card by around the 82:00 mark. It's about two-and-a-half minutes to get to the decision.

But, unlike the first incident when Elfath seems to be simultaneously confronting players and listening to the VAR, the second time around is mostly the referee talking to the voice in his head. For more than two minutes. That feels like a significant break in the flow of the game. Everyone is waiting for the referee. The ensuing free kick is taken at about 82:40 on the game clock: more than three-and-a-half minutes after the original foul.

There is no time limit on VAR deliberations. Some will take longer than others. Fair or not, some will simply feel longer than others - and affect fan, player, and coach assessments of the technology accordingly.

5. Get used to this signal

The official sign the ref is going to take a look at the tape,

WATCH: SECOND Video Assistant Referee use. This time a yellow given#NYvORL pic.twitter.com/rbaEeNPuwM — NYRB II (@NYRBII) August 13, 2016

6. They're not kidding about the VAR checking all the camera angles

Here's a behind the scenes look at the Video Assistant Referee at the @NYRBII vs @OrlandoCityB match! #NYvORL pic.twitter.com/UIDtBbm0PW — USL (@USL) August 13, 2016

7. There is jargon

@Once_A_Metro Key technical term here. VAR can check call, but only head referee can review. — Nicholas Murray (@NJEMurray) August 13, 2016

Important to note. The VAR reviews everything the VAR is supposed to review. But in the IFAB lexicon, "review" is what is happening when the center ref is notified of an issue by the VAR, and decides stop and listen or go look at the tape.

If there is nothing for the VAR to report - as presumably was the case for NYRB II's second-half penalty, which brought no trip to the endline from Elfath - there is no "review". The VAR has simply "checked".

8. All of this can change

The series of games showcasing VAR is a trial. It's purpose is gather evidence and experience. And evidence and experience informs change. Unless you are Alexi Lalas standing firm behind a heat-of-the-moment comment for the purpose of sustaining some imagined infallibility, new information does have an effect on what you think and how you act.

Over the course of the VAR-influenced games to be staged at Red Bull Arena, we can expect to see a few challenges to the system that has been worked out to date. One would imagine IFAB is hoping for such challenges. Easier to fix a glitch or unintended consequence exposed at the lowest-attended games in the third division of US Soccer than at an international tournament.

So what we learned from this game, we may have to unlearn or relearn in due course.