In the first best-of-seven series in WNBA history, the Phoenix Mercury are attempting to do something that no team has ever done in the WNBA or NBA: climb out of an 0-3 hole in the Finals.

They had an opportunity to take Game 3 on Wednesday. Phoenix rallied from down 17 in the fourth quarter to tie the score with just five seconds left in regulation, but heroics from A’ja Wilson — a jaw-dropping fadeaway over the outstretched arms of Alyssa Thomas and DeWanna Bonner — now have the Mercury staring elimination in the face.

They have shown signs of life in this series, fighting back against the Aces’ dominance with two of the three games decided by a combined five points. And yet, Phoenix has failed to get a win. Now, its path to extending the series becomes even harder without forward Satou Sabally, who has been ruled out of Friday’s game with a concussion.

What adjustments will the Mercury need to make without Sabally? What X factors have the Aces one win away from their third championship in four years? ESPN’s Alexa Philippou, Kendra Andrews and Charlie Creme preview the potential keys to Friday’s Game 4 (8 p.m., ESPN).

With Satou Sabally sidelined, what adjustments could the Mercury make? Who has to step up?

Alexa Philippou: The Mercury could start either Bonner or Sami Whitcomb in place of Sabally, or both could get the nod if Natasha Mack comes off the bench. That’s the lineup Phoenix closed with after Sabally went down, with Whitcomb checking in for Sabally and Mack sitting the whole second half in place of Bonner.

While Bonner had her most impactful showing of the series with 25 points in Game 3, including five straight for Phoenix to close the game, Whitcomb has been a nonfactor against Las Vegas. She has scored just six points on 2-for-16 shooting this series and hasn’t gotten on the board since Game 1. The Mercury could definitely use her scoring punch from deep to regain some juice offensively.

Kendra Andrews: Alexa is right that the Mercury need more from their bench, but there is added pressure on Thomas and Kahleah Copper.

For much of these playoffs, the Mercury have gone as Thomas — their “engine” — has gone. And so far against the Aces, she hasn’t had the same level of dominance she had heading into the Finals. Her postseason averages of 18.6 points and 9.1 assists fell to 13.0 points and 7.7 assists in this series.

In Game 4, Thomas has to bring more controlled physicality, where she can be up on her defender — or whoever she is defending — but not get called for fouls so she can get into the spots she thrives in and takes over.

Copper has scored 21, 23 and 17 points, respectively, in the first three games of the Finals. Without Sabally’s team-high 21.6 points per game (in this series), the Mercury will need Copper’s cutting and finishing even more.

Where have the Mercury struggled defensively?

Andrews: Copper said that the Mercury have lost some of their connectivity and communication on the defensive end. They entered the Finals with the highest defensive rating in the postseason, holding opponents to 75.9 points per game. But they gave up 89 points in Game 1, 91 points in Game 2 and 90 in Game 3 of this series.

It would be unfair to say that their biggest priority on defense is everything, but as soon as they resolve one problem, another seems to pop up. In Game 3, their first-half issue was defending the 3-point shot. The Aces got anything they wanted from distance, hitting nine 3s in the first 20 minutes, seven of which were uncontested — the most 3s they have hit in one half and the most uncontested 3s they have had all season.

The Mercury were also a step slow on closing out Wednesday. They were also slow on loose balls, allowing the Aces to get 12 offensive rebounds and 14 second-chance points.

At this point in the season, the Mercury can’t afford to lack connectivity on defense, or “lose edge,” as Thomas said they did in Game 3.

Charlie Creme: Given the way Wilson is playing and Las Vegas is shooting from the perimeter, Phoenix coach Nate Tibbetts is caught in a strategic conundrum. When he defends Wilson with one player, which has been the case for most of the series, the other four Phoenix defenders must lock up the rest of the Aces’ attack. Wilson cooking is one thing, but when Jackie Young and Chelsea Gray are, too — or Dana Evans and Jewell Loyd are producing — no team has much of a chance against the Aces.

Another option is throwing consistent double-teams at Wilson, preventing Young’s defender from helping elsewhere — and then hoping the Aces’ open looks don’t fall. Hope is never a sound strategy, but the Mercury will need plenty of good fortune to come back in this series.

If Tibbetts employs either of these philosophies, it must be a full commitment. Playing somewhere in between leaves too many holes on defense, which is what we have seen in the first three games.

What have been the X factors in the first three games?

Creme: Heading into this series, I thought the championship would be decided by the play of each team’s big three. For the most part, it has played out that way — Wilson and Young have been the series’ best players. But there have been two ancillary aspects to this matchup that have greatly contributed to Las Vegas’ success.

One is 3-point shooting: Las Vegas has made 12 more 3s than Phoenix and shot them at a higher percentage (35.1% to 25.0%). The other is bench production: The Aces’ bench has outscored the Mercury’s reserves 79-51 — and nearly half of the Phoenix total came from Bonner in Game 3. (We already outlined Whitcomb’s struggles above.)

Loyd might feel like a de facto starter (she has averaged more than 31 minutes per game), but her move to a reserve role was key to the Aces’ turnaround this season and it has continued in the postseason. She has made nine 3-pointers in the three Finals games and is averaging 14.3 points. Evans’ 21 points in Game 1 — many of which came via 5-of-6 shooting from deep — was a big reason Las Vegas got off to a good start.

With the better-performing stars, the more productive reserves and the more accurate shooting, it’s no surprise Las Vegas is on the brink of the title.