Joe Denly hit 188 not out as the England Performance Programme squad recovered from early trouble to reach 345-7 on the opening day of their match against the Nashua Titans in Pretoria.
Kent batsman Denly was given solid support from county colleague James Tredwell in a seventh-wicket stand of 187 as the tourists scored quickly throughout.
Basheer Walters gave the Titans a promising start, removing openers Michael Carberry and Stephen Moore for 11 and one respectively.
And things got progressively worse for the EPP as Andrew Gale and Rory Hamilton-Brown came-and-went cheaply before Somerset wicketkeeper Craig Kieswetter chipped in with 25.
Denly, batting at three, stood firm to see his side through to lunch on 73-4.
The Canterbury-born right-hander's knock, which represents his highest ever score although the game does not carry first-class status, saved the day with four sixes and 23 fours to race past three figures.
Tredwell fell for 70 just before stumps, Walters returning for a third wicket, but Yorkshire's Ajmal Shahzad joined Denly through to the close.