The win-rate trend chart is the first thing most players check after logging a new match. It is also the chart most likely to be misread. A line that goes up over twenty matches feels great, but on its own it tells you almost nothing about whether you are improving. This article walks through exactly what the line represents, how it is computed, and the five questions you should ask before you let the curve change your mood.
What you are actually looking at
Each dot on the chart is a match, plotted in chronological order on the x-axis. The y-axis is your rolling win rate at that point in time — not your win rate for that single match. By default the rolling window is your full history filtered by the controls at the top: format (Singles, Doubles, Mixed) and competitiveness (Friendly, Official). The curve smooths between dots so you see a trend instead of a sawtooth.
A green dot means you won that match. A red dot means you lost. A grey dot is a match that ended without a winner (rare — usually an interrupted match that you marked as a draw). The colour of the line itself shifts subtly when the underlying mix changes: a long stretch against the same opponent on the same surface tends to be flatter and less informative than a varied stretch.
How the rolling win rate is computed
For every match in chronological order, Tennis Log takes the matches up to and including that match (within the active filter), counts decided ones, and divides wins by decided matches. Draws and unfinished sets are excluded so a "win rate" of 60% truly means *six out of ten decided matches won*, not *six wins and four interrupted matches that happened to end with you ahead*.
Because the calculation runs cumulatively, early dots are extremely volatile. A loss in match #3 drops your rate by 33 percentage points. The same loss in match #50 barely registers. This is the single most important thing to understand about the chart: the same vertical movement means very different things at different x-positions.
Question 1: Is there actually a trend?
A trend needs three things: enough matches (at least 15 in the filtered view), a directionally consistent slope, and consistent variance. Look for:
- The most recent 10 dots clustered higher than the previous 10
- The amplitude of the wiggles shrinking, not staying constant
- No huge gaps in time (a six-month break and then a new cluster is two separate trends, not one)
If your chart is twelve matches across two years with three different surfaces mixed in, it is not a trend — it is a scatter plot. Filter harder.
Question 2: Is the trend caused by opponent quality?
This is the dangerous one. A rising win rate against weaker opponents is not improvement, it is selection bias. Cross-reference your trend with two things:
- Your opponent strength distribution (do the recent matches lean toward players you usually beat?)
- Your performance radar (is the green-vs-blue gap actually shrinking?)
If your win rate climbed from 45% to 60% but your performance radar shows the same gap between you and your opponents, you simply played easier opponents. That is fine for confidence, but it is not skill growth.
Question 3: Did anything in your life change?
Tennis Log lets you mark match conditions (slept well, fasted, anxious, napped, heavy meal). These are not gimmicks — they are some of the strongest predictors of amateur win rates in the data. When you see a sudden three-month bump in the trend, check the conditions of those matches. Often the answer is: "I started sleeping seven hours instead of five." That is a real win-rate driver, but it is a *lifestyle* finding, not a technique finding. Mistaking one for the other leads to wrong training.
Question 4: Which format is driving the curve?
Click the Singles / Doubles / Mixed toggle and watch the line redraw. Most players have wildly different win rates per format. A 60% overall win rate often hides a 70% singles rate and a 45% doubles rate. The aggregate number is meaningless for training — train against the format with the worst rate, not the best.
Question 5: Is the line moving for the right reasons?
A rising win rate paired with:
- Rising hold % = your serve is genuinely better
- Rising break % = your return game is genuinely better
- Flat hold + flat break = you got lucky in tiebreaks and deciders; expect regression
The trend chart is the *outcome*. Hold % and break % are the *cause*. Always read them together.
Common mistakes when reading the chart
- Celebrating a 3-match streak. Three is noise. Ten is signal. Thirty is a verdict.
- Comparing the first match to the latest. The first match has zero data behind it. It is not a number worth comparing.
- Looking only at the cumulative line. Switch to a tighter filter (e.g. Singles + Official + last year) before you draw conclusions.
- Reading the curve without the dot colours. A flat line at 55% can hide a brutal 0-4 streak followed by a 4-0 recovery — the dots tell that story; the line hides it.
- Ignoring grey dots. A draw or unfinished match might be a story you need to revisit. Click it.
How to actually use the chart for improvement
Once a month, do this five-minute review:
1. Set the filter to your most-played format and most recent year. 2. Note the rolling win rate at the rightmost dot. 3. Compare it to the value 10 matches ago. Note the delta. 4. If positive: open the performance radar and find which skill gap shrank. That is what is working — keep doing it. 5. If negative: open the per-game success chart and find where games are leaking. That is your training target for the next month.
The win-rate trend is the headline. The supporting charts are the article. Read both, or read neither.
Why we built the chart this way
We considered showing only a 10-match rolling window (more responsive to recent form) and only a cumulative line (more stable). We chose the smoothed cumulative because, in user testing with amateur players, the cumulative view caused fewer panic decisions. Amateur tennis improvement happens on the order of months, not matches. A chart that responds in months reflects that timescale honestly.
If you would like both views, we are happy to add a rolling-window toggle — open a request on the contact page. For now: read it slowly, ask the five questions, and trust the long-run direction over the short-run wiggle.