The main intrigue here is not the three places separating them in the rankings, but the calibre of their opponents recently: Lehecka has so far come through the draw without dropping a set, while Jodar has beaten Lorenzo Musetti twice in a week and reached the Washington final between those matches.
Jodar is not currently playing like a tennis player who has only just broken into the top 20. At 19, he has already risen to 15th in the rankings, and his last week and a half has been stronger than Lehecka's: he reached the ATP 500 final in Washington, beating Arthur Fils and Lorenzo Musetti along the way, and then continued winning in Montreal without missing a beat.
In Canada, the Spaniard first came from a set down to beat Corentin Moutet (4:6, 6:1, 6:3), then beat Musetti again (6:4, 6:3). In the latter match, Jodar converted six of 11 break-point opportunities and struck 27 winners. That is exactly what is needed against Lehecka: not merely holding serve, but constantly making the Czech play an extra ball in his service games.
Lehecka has also progressed smoothly: Vit Kopriva was beaten 6:4, 6:2 and Alexander Blockx 6:3, 6:4. He has not dropped a set, and against Blockx the Czech was not broken and won 87% of points behind his first serve. However, his route through Montreal has so far been considerably calmer. Jodar has already been tested by the Washington final and two successive matches against Musetti, who is now alongside them in the top 15.
There is a downside for the Spaniard in terms of workload, but it does not look critical. The match against Musetti lasted only one hour and 35 minutes, and Jodar then had a day without a singles match. He has maintained a high tempo throughout the American hard-court swing and does not fall apart after losing sets.
There is no gulf in class here: Lehecka is 12th in the world and Jodar 15th. Current form should therefore be decisive, and the Spaniard's is better. Jodar is more tenacious on return, has beaten higher-ranked opponents more often recently and is currently playing with the confidence of someone who has already ceased to be a surprise. In this pairing, Rafael's win looks stronger than Lehecka's status and fresher legs.