Rira Kosaka vs Sayaka IshiiPrediction, Head-to-Head Results, and Stats
Rira Kosaka and Sayaka Ishii have met 1 time since 2026; Sayaka Ishii leads 1–0. Across all meetings Kosaka has taken 0 sets to Ishii's 2. Their most recent meeting: Sayaka Ishii won at W50 Nanao (2026).
Spread & Straight-Sets Form
Completed best-of-3 matches · Last 12 months
| Indicator | Kosaka | Ishii | ||
|---|---|---|---|---|
| Indicator | Rira Kosaka | Sayaka Ishii | ||
| Wins in straight sets | 78% | 14/18 | 65% | 17/26 |
| Wins a set when losing | 47% | 9/19 | 17% | 4/23 |
| Goes to a deciding set | 35% | 13/37 | 27% | 13/49 |
| Covers −1.5 sets as favorite | 33% | 1/3 | 32% | 8/25 |
| Covers +1.5 sets as underdog | 69% | 11/16 | 44% | 7/16 |
| Tiebreak sets won | 33% | 1/3 | 53% | 8/15 |
| Wins after taking set 1 | 84% | 16/19 | 91% | 20/22 |
| Wins 2-0 after taking set 1 | 74% | 14/19 | 77% | 17/22 |
Colored rows are higher-is-better: green above 50%, red below. Favorite/underdog set by book odds; cover rows count only matches with odds on record. Head-to-head: 1 of 1 completed meetings ended in straight sets (Kosaka 0, Ishii 1).
Style Matchup
Playing styles and historical archetype record
Kosaka
🧱 The Wall
Ishii
💥 Big Hitter
Matchup analysis
The 💥 Big Hitter archetype wins about 59% vs 🧱 The Wall across 910 matches in our dataset: a stylistic lean toward Sayaka Ishii.
Big Hitter players often use power groundstrokes and high winner count to pressure the the wall's elite returner.
Previous meetings
1 career meeting, newest first
Sep 22, 2026
W50 Nanao
? Carpet · 3rd Round Qualifying
Prop Research
Hit rates on common betting markets · Last 90 days
| Outcome | Kosaka | Ishii | ||
|---|---|---|---|---|
| Outcome | Rira Kosaka | Sayaka Ishii | ||
| 1 or more | 40% | 4/10 | 79% | 15/19 |
| 3 or more | 10% | 1/10 | 26% | 5/19 |
| 5 or more | 0% | 0/10 | 11% | 2/19 |
| 10 or more | 0% | 0/10 | 5% | 1/19 |
| 15 or more | 0% | 0/10 | 0% | 0/19 |
| 20 or more | 0% | 0/10 | 0% | 0/19 |
Player ROI
Hypothetical if you put 1u on each player to win every one of their matches · Last 90 days
| Metric | Kosaka | Ishii |
|---|---|---|
| W-L | 3–6 | 13–8 |
| Avg odds | 3.92 | 1.56 |
| ROI % | -34.2% | -12.1% |
| Units P/L | -3.08u | -2.55u |
Small sample: ROI stabilizes with more matches; fewer than 10 in the window is noisy.
Travel
Last 30 days
| Metric | Kosaka | Ishii |
|---|---|---|
| Countries | 3 | 2 |
| Events | 3 | 2 |
| Matches | 8 | 8 |
| Distance | — | — |
| Route | AUT → ECU → POR | ESP → AUT |
Host country from each tournament in the last 30 days, including the current event even when a player arrived on a bye. Route is the order of countries visited; consecutive stops in the same country are shown once. Distance is the great-circle total between host cities, shown only when every stop in the window is geocoded. A rough fatigue signal, not a headline stat.
Common opponents
Results vs. opponents both players faced · Last 12 months
Across 3 shared opponents, both Kosaka and Ishii posted a 67% win rate.
| Opponent | Kosaka | Ishii |
|---|---|---|
| Natsuho Arakawa | W 36 63 62 | W 16 61 104 |
| Mari Muto | W 62 76 | W 60 60 |
| Elena Micic | L 62 36 46 | L 36 57 |
Recent Form
Last five matches per player
Haruka Kaji
W35 Wagga Wagga · 1st Round
Oct 7
Sera Nishimoto
W35 Wagga Wagga · 3rd Round Qualifying
Oct 5
Zoe Theodorakopoulos
W35 Wagga Wagga · 2nd Round Qualifying
Oct 5
Haruna Arakawa
W35 Wagga Wagga · 1st Round
Sep 30
Remika Ohashi
W35 Wagga Wagga · 3rd Round Qualifying
Sep 29
Shante Lai
W35 Wagga Wagga · 2nd Round Qualifying
Sep 28
Sayaka Ishii
W50 Nanao · 3rd Round Qualifying
Sep 22
Natsuho Arakawa
W50 Nanao · 1st Round Qualifying
Sep 21
Hiromi Abe
W50 Nanao · Semifinals
Sep 26
Rion Itaya
W50 Nanao · Quarterfinals
Sep 25
Natsumi Kawaguchi
W50 Nanao · 2nd Round
Sep 24
Nagi Hanatani
W50 Nanao · 1st Round
Sep 23
Rira Kosaka
W50 Nanao · 3rd Round Qualifying
Sep 22
Miku Suzuki
W50 Nanao · 1st Round Qualifying
Sep 21
Hiromi Abe
W35 Kyoto · Quarterfinals
Sep 18
Amelia Rajecki
W35 Kyoto · 2nd Round
Sep 17
Win rate
Matches, sets and games won · Last 12 months · 37–49 matches
| Metric | Kosaka | Ishii |
|---|---|---|
| Matches won | 49% | 53% |
| Sets won | 52% | 50% |
| Games won | 50% | 51% |
Record by tier
Head-to-head record by tournament tier
| Stage | Kosaka | Ishii |
|---|---|---|
| ITF W50 | 0 | 1 |
By surface
Head-to-head record per surface
| Surface | Kosaka | Ishii |
|---|---|---|
| Carpet | 0 | 1 |
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