US Open Men's Singles Quarter-Final Tips: Djokovic takes 7-0 lead into Fritz clash

• Djokovic huge favourite against Fritz

• Serve battle key for Fritz if he is to cause a shock

• Tiafoe expected to get past countryman Shelton

Taylor Fritz v Novak Djokovic

It's action from the bottom half of the draw on day nine, with two matches taking place - Frances Tiafoe versus Ben Shelton, and Taylor Fritz clashing with Novak Djokovic. The latter meeting is the first on the schedule at 1830 UK time, with Djokovic taking a 7-0 career lead over Fritz onto court.

In those seven matches, Djokovic is 15-2 up in sets but only has played twice against the American since Fritz broke into the top 10, including this stage in Cincinnati several weeks ago, when Djokovic eased to a 6-0 6-4 win, priced up at around 1.251/4 pre-match.

Second serve performance a key metric here

Djokovic is shorter-priced today, at a current 1.171/6, which makes sense given the straightforward nature of that win, and also the longer best of five set format, which tends to favour the 'better player'.

Having a look at the previous meetings, the two more recent encounters saw Fritz really struggle both on serve and return, holding 65% and breaking 15%, and winning just 43% of points, and 38% of games.

His second serve in particular has been exposed by the tournament favourite, winning just 31% of second serve points, and that will need to markedly improve if there is going to be a shock tonight.

Frances Tiafoe v Ben Shelton

Following this, there is an all-American clash between Frances Tiafoe and Ben Shelton, with the higher-ranked Tiafoe a solid market favourite at 1.422/5. The duo have never met before in professional tennis, and Tiafoe looks a very justified favourite at market prices, given his significant advantage on return data.

Shelton has hugely surpassed expectations this tournament (and at the Australian Open) but has considerably worse data (again on return mostly) than Tiafoe in the tournament so far, and it would be a surprise if he was to continue a slightly random run with another victory later on today.