Doubles Wins and Davis Cup Results

Today, Tomas Berdych added another chapter to his outstanding Davis Cup doubles career, partnering Radek Stepanek to give his Czech Republic a 2-1 lead in this weekend’s Davis Cup final.

The absence of Janko Tipsarevic meant that the doubles rubber was particularly crucial.  While Novak Djokovic will probably defeat Berdych tomorrow, Stepanek is equally likely to dismiss Dusan Lajovic, giving the Czechs a second consecutive Davis Cup title.

Since the Saturday doubles match is so often a pivotal juncture in a Davis Cup tie, I was curious whether the doubles match was particularly predictive of the end result.  If you’re a believer in momentum, it would seem possible.

However, if a side is to take a 2-1 lead, it’s better to win two singles matches and lose the doubles than to drop one of the singles matches.  Or, to put it another, probably more accurate, way: It’s best to have a squad that dominates the singles.  (Stunning insight, I know.)

There have been 435 World Group ties (including playoffs) since 1981 in which the outcome was undecided after the doubles match.  In 296 of those, the two sides split the singles.  In the other 139, one side swept the first-day singles and the opposing team won the doubles.

Of the first group of 296, the side that won the doubles won 80.4% of ties.  That pales in comparison to the singles-sweeping sample. Of those 139 ties, the side that won both singles and lost the doubles proved triumphant 93.5% of the time.

This shouldn’t be too surprising.  Momentum or no momentum, the third day of a Davis Cup tie is nothing but singles matches.  When the outcome is to be decided by two singles rubbers, would you rather have two great singles players or a pair of momentum-swaying doubles players?

Fortunately for the Czechs, 80% is still awfully good, and it probably understates the likelihood that Stepanek will beat Lajovic tomorrow.   Nice as it would have been to sweep opening-day singles, it helps to have a backup plan when Djokovic is playing for the other side.

One thought on “Doubles Wins and Davis Cup Results”

  1. Wonderful!

    Every time – like today – when I hear the announcers throw out a half-baked stat about “only five teams losing the doubles and winning the final in the modern era”, I wonder what the real statistician would say. And as usual, you expose how shallow their banter is.

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