How to bet on tennis
Tennis has no draw and no team, so the price on a match is a straight opinion of one player against another. What makes it hard is that the same two players are a different match on a different surface. The book knows that. The public mostly bets the name.
Three games on three surfaces
Tennis is played on clay, grass and hard courts, and they change who wins. Clay is slow and the ball bounces high, which rewards long rallies and players who can defend. Grass is fast and low, which rewards a big serve and short points. Hard courts sit in between. A player's ranking is built across all three, so it tells you less about any one of them than people think.
When I priced a tennis match I'd start with each player's record on that surface, then the head-to-head on that surface, and only then the ranking. Some players have opponents they just don't beat, whatever the rankings say, and tennis is one of the few sports where a matchup like that holds up for years. The public works the other way round: ranking first, name first, surface last. The biggest gaps between the price and the player tend to open at the start of each surface's season, before the public has caught up with who can play on it.
How a match price is built
A tennis match is a set of sets, and that is where the arithmetic is. Say a player wins any one set against this opponent 60 percent of the time (treating each set as separate, which is close enough for this). In a best-of-three match she wins 64.8 percent of the time. In best of five, 68.3 percent.
| Wins a set | Best of three | Fair price | Best of five | Fair price |
|---|---|---|---|---|
| 55% | 57.5% | -135 | 59.3% | -146 |
| 60% | 64.8% | -184 | 68.3% | -215 |
| 65% | 71.8% | -255 | 76.5% | -325 |
| 70% | 78.4% | -363 | 83.7% | -513 |
The longer the match, the more the better player wins, and the shorter the price. That is why the favorites at the majors, where men play best of five, are priced so short in the early rounds. It is also why I'd be wary of an upset price in a five-set match: the underdog has to stay good for a long time.
The price of a short favorite
The tennis bet I watched the public make more than any other was a parlay of heavy favorites. Four players at -400 each, $100 on the ticket, and it pays $244.14. It feels safe, because every one of them should win.
Work it through. At -400 the book is saying each one wins 80 percent of the time, cut included. If each one truly wins 78 percent, the four all win 37.0 percent of the time, and on average the ticket returns $90.37 for every $100 you put in. You lose about $9.63 per $100, more than twice what you'd give up on a coin-flip bet at -110. And a straight bet at -400 is no better in its own way: you risk $400 to win $100, so one loss wipes out four wins.
I didn't like laying more than about -250 on a tennis player, ever. Anyone can lose a set to nerves, an injury or a bad day, and at -400 there is no room for any of them. The parlays page shows how the cut grows with each leg.
Form, schedule and the body
Tennis players play nearly every week, and form shows up quickly. What the price is slow to catch is fatigue: a player who went three hours in the last round, or played doubles too, or came straight from a long run at an event on the other side of the world. I'd check the previous match's length before the head-to-head.
Injuries are the other half. Players retire mid-match more often than in most sports, and the settlement rule for that varies by book. The tennis betting sites page covers it, and you should read it before your first bet. A player who withdraws before the match starts is a void bet at most books.
Tennis runs almost all year, which makes it easy to bet a match every day without an opinion on any of them. Keep each bet to 1 or 2 percent of your bankroll and save your money for the surface and the players you actually know.