Las Vegas Aces vs Phoenix Mercury: WNBA prediction

Las Vegas Aces and Phoenix Mercury meet on September 24, 2026 at 11:00 PM Brasília time in Phoenix, on the final day of the WNBA regular season. The league scheduled the fourth meeting of the year between the teams for 10:00 PM ET, and the U.S. national broadcast is on USA Network. This analysis was closed on September 20, 2026.

The central read favors Las Vegas in the game-winner market. The main reason is the season-long efficiency gap on a per-possession basis, reinforced by the competitive context: the Aces had already clinched a playoff spot and were still playing for seeding, while the Mercury were already in the draft lottery group.

Prediction and best pick

Main pick	Las Vegas Aces to win
Market	Game winner (moneyline)
Confidence	64%
Conservative probability	64%

No market price was used to select the pick. Because no current and stable spread or total line for September 24 could be verified, those markets did not receive a specific line in the final ranking and no edge or EV calculation is presented.

Why this is the best pick

Season efficiency: in Basketball Reference's common 40-game sample, Las Vegas had a 113.4 ORtg and 108.3 DRtg, for a +5.1 net rating per 100 possessions. Phoenix had a 106.3 ORtg and 110.2 DRtg, for a -3.9 net rating. The baseline net-rating gap was 9.0 points per 100 possessions.
Comparable pace: the same sample recorded a 79.4 Pace for Las Vegas and 79.0 for Phoenix. That reduces the risk that the efficiency comparison is being driven only by very different playing speeds.
Post-break update: the Aces returned from the break with a 114-77 win at Seattle on September 17 and moved to 28-13. Phoenix reached 15-27 after an 87-82 loss at Dallas on September 19.
Recent matchup: Las Vegas won the two most recent meetings this season, 86-76 in Phoenix on June 17 and 106-58 in Las Vegas on July 11. Phoenix won the first meeting 99-66 on May 9, so head-to-head was given low weight in the model.
Competitive context: the WNBA listed Las Vegas among the playoff teams and Phoenix among the lottery teams. Entering the break, the Aces were still pursuing a higher seed.

Among the valid markets that could be modeled without inventing a line, the game-winner market produced the highest final conservative probability.

Match context

The game closes the regular season on September 24. The official WNBA schedule lists Las Vegas at Phoenix at 10:00 PM ET, equivalent to 11:00 PM in America/Sao_Paulo. The matchup is also a rematch of the 2025 Finals and is part of USA Network's national schedule.

Roster context still requires an update. The WNBA reported that NaLyssa Smith, who was averaging 11.7 points and 6.4 rebounds across 38 games, is out for the rest of the season with a leg injury. For Phoenix, Kahleah Copper missed the September 19 game with a groin issue, and her availability for September 24 had not been confirmed when this analysis closed. Las Vegas still plays on September 20 and September 22 before visiting Phoenix, which can affect rotation, fatigue and the need for a result.

Form and data that matter

Team	ORtg	DRtg	Net Rating	Pace
Las Vegas Aces	113.4	108.3	+5.1	79.4
Phoenix Mercury	106.3	110.2	-3.9	79.0

The table uses the same provider and the same 40-game sample to preserve comparability. Las Vegas also posted a 54.3% offensive eFG% in that sample with a 13.4% TOV%, while its overall efficiency profile remained stronger than Phoenix's. The most recent results were used only as a form update, not as a replacement for the season baseline.

Pace, efficiency and matchups

Both teams operated near 79 possessions per 40 minutes in the baseline, so the quality gap appears mainly in efficiency rather than volume. Las Vegas scored 113.4 points per 100 possessions and allowed 108.3; Phoenix scored 106.3 and allowed 110.2. That profile creates a structural advantage for the Aces on both ends.

NaLyssa Smith's absence removes interior scoring and rebounding from Las Vegas, which prevents a higher confidence level. At the same time, Copper's status can change Phoenix's offensive ceiling. For that reason, the model does not treat the 106-58 July score as representative by itself and does not make head-to-head results a dominant factor.

How the prediction was calculated

The basketball model starts with per-possession metrics. The baseline combined ORtg, DRtg and Pace in the common 40-game sample, then incorporated recent form, home court, competitive context, low-weight head-to-head information and roster availability. The 9.0-point net-rating gap per 100 possessions was the strongest quantitative signal.

That evidence produced a P_raw of 68% for a Las Vegas win. Evidence quality was assessed at Q = 0.81: source recency and sample size were strong components, while roster certainty was discounted because Copper's status remains open, Smith is out, and Las Vegas still has games before September 24.

Applying conservative shrinkage for a binary event gives P_adj = 0.50 + 0.81 x (0.68 - 0.50) = 64.6%. A 64% cap was then applied to reflect the additional rotation and availability uncertainty on the final day of the regular season. Therefore, P_final = 64% and the published confidence is 64.

What can derail the pick

Las Vegas could reach the finale with its seed already settled and reduce starter minutes.
Kahleah Copper's status could improve Phoenix's offense versus the scenario used today.
NaLyssa Smith's absence reduces the Aces' depth, rebounding and interior efficiency.
Las Vegas games on September 20 and September 22 can create fatigue, new absences or a change in competitive priority.
Phoenix's home court and single-game shooting variance can offset part of the efficiency advantage.

Conclusion

Main pick: Las Vegas Aces to win, with 64% confidence. The per-possession efficiency advantage and competitive context support the selection, but the probability was capped to incorporate roster and rotation uncertainty that can still change before September 24.