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Kayla Day vs Kimberly Birrell — Japan Open - Osaka Round of 32

Japan Open - OsakaR32HardTue 20 Oct · 14:30
Kayla DayWTA #119 · USA46%
VSToss-up
Kimberly Birrell(3)WTA #41 · AUS54%
Win probabilityWho is more likely to winToss-up
46%54%

No meaningful edge. Serve performance in the first set is the likeliest tiebreaker.

Umpiry ScoreMatchup strength, 0–10 · not a probability
Day K.5.2/10
Clear underdog
Birrell K.7.0/10
Strong advantage
Why
Surface+176 Hard Elo edgeSupports Birrell K.
Overall ratingOverall Elo 1754Supports Birrell K.
Recent runLost last 2Informative
Head-to-headNo prior meetingsBoth players
This eventDidn't play here last yearBoth players
ELO1 784
Hard ELO1 683
Last 107–3
Age27
Height173 cm
PlaysLeft
EarningsCareer $1.6M2026 $261K
ELO1 835
Hard ELO1 743
Last 107–3
Age28
Height170 cm
PlaysRight
EarningsCareer $3.2M2026 $1.1M

Kayla Day faces Kimberly Birrell in the Japan Open - Osaka round of 32 on hard. Kimberly Birrell holds the paper edge — ranked #41, a roughly 180-point hard Elo advantage. Recent hard form is closely matched.

Key context

  • Freshness: Workload contrast: Kayla Day 48 games in 14 days, Kimberly Birrell 35.
  • Serve & return: Serve-return mismatch: Kayla Day grades 60 on serve, Kimberly Birrell 45 on return.
  • Surface form: Both 7 of 10 on hard recently — court-specific quality nearly identical despite the ranking gap.

Common opponents

2 shared · last 12 months

Day K. and Birrell K. faced 2 of the same opponents in the last 12 months. Day K. went 1–1 (50%) against them, Birrell K. 1–1 (50%).

1–150%Day K. · better vs 1Record vs common opponents1–150%Birrell K. · better vs 1
Vs common opponents · derived from scorelines
3–3Sets2–2
27–29Games17–18
1–1Deciding sets0–0

Only 2 common opponents — too few for any conclusion. Shown without assessment.

Head-to-head

They have not met before.

Evidence

Day K.Birrell K.
FormLast 10 matches each · 2026
Win–loss7–37–3
Season win rate70% (45–19) (ahead)54% (30–26)
RatingUmpiry ELO
Overall ELO17841835 (ahead)
Hard-court ELO16831743 (ahead)
Serve vs returnLast 61 vs 53 matches
1st-serve points won67% (ahead)64%
Return points won46% (ahead)44%
Aces / match3.9 (ahead)1.9
ClutchLast 61 vs 53 matches
Break points saved59% (ahead)53%

Draw

Odds

Conditions

14:30 local
SurfaceHard
Forecast26°C · Mainly clear
Wind2 km/h
Humidity72%

Freshness

Last 7 & 14 days
Day K.Birrell K.
1Days since last match6 — fresher
2Matches · 7 days1 — fresher
48Games · 7 days35 — fresher
2Matches · 14 days1 — fresher
48Games · 14 days35 — fresher
Green marks the fresher player.

Cite this

Umpiry, "Kayla Day vs Kimberly Birrell — Japan Open - Osaka Round of 32", https://umpiry.com/match/2026-10-20/birrell-vs-day-japan-open-osaka-r32?utm_source=cite (as of 20 October 2026).