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World No. 2 is Herbert's highest career doubles ranking. This means that at some point in his career, he was ranked as the second-best doubles player in the world. Doubles rankings are based on a player's performance in doubles tournaments, such as Grand Slams, Masters 1000 events, and ATP 500 events. Herbert has won several doubles titles throughout his career, including the 2015 US Open and the 2019 Wimbledon Championships.