Schwartzman has reached the quarter-finals of two Masters tournaments this season, including in Montreal earlier this month where he frustratingly lost to Dutchman Robin Haase, ranked below him, after beating world No. 8 Dominic Thiem.

The secret of Schwartzman's success was revealed on the ATP site in an article entitled 'Return giant of 2017'. Standing at 5ft 7in Schwartzman of Argentina, the shortest player in the top 100, has the world's best record in returning serves and is the world's fifth best player in breaking opponents' serves.

Israel's Dudi Sela, ranked 70, will be hoping to repeat his Wimbledon form where he reached the third round.

Last week, in an attempt to win the Vancouver Challenger for the fifth time he was bundled out in the round of 16 by Britain's Liam Broady, ranked 256.

Canada's Israeli-born Denis Shapovalov who reached the semi-finals of the Canada Open must play in the US Open qualifiers because he was ranked outside of the top 100 last month.

In the women's tournament, Italy's Camila Giorgi will have her tail up after rising 13 places in the rankings to 69 after reaching the round of 16 at last week's Cinicnatti Masters, where she lost in three sets to world number 1 Karolina Pliskova.