Shai Hope and Roston Chase filed an impressive application for inclusion in next week's first Test at Edgbaston on a worrying day for the West Indies' main strike bowler during the second day of their tour game against Derbyshire.
After Hope and Chase scored unbeaten centuries in the tourists' 427-3 declared, Shannon Gabriel bowled 20 no-balls and conceded 64 runs from his nine overs.
Derbyshire were nevertheless bowled out for 181 - Calum Brodrick top scoring with 52 on his first-class debut - with skipper Jason Holder the stand-out bowler with 3-48 - but Gabriel's performance in his first game of the tour will be a concern with the opening Test against England only five days away.
Holder chose to bat again rather than enforce the follow-on and Kraigg Brathwaite failed for the second time in the match before the tourists closed on 60-1 in their second innings, a lead of 306 going into the third and final day of the game.
Although Brathwaite managed only 14 runs in the match, the rest of the batting looks in decent shape with Hope and Chase reaching their sixth centuries in first-class cricket off successive balls in the 11th over of the day.
The Barbadian right-handers added another 87, with Hope unbeaten on 107 and Chase 110 to take their unbroken stand to 196 before Holder called a halt.
Gabriel's problems began in his third over from the City End when he twice lost his run-up, bowled five no-balls and was straight driven for two fours by 22-year-old opener Charlie MacDonnell.
Kemar Roach had MacDonnell caught behind for nine and a three-wicket burst from Holder saw the tourists take six wickets between lunch and tea through disciplined, aggressive fast bowling to reduce Derbyshire to 115-7.
All seven wickets fell to catches behind the wicket, with five for wicketkeeper Shane Dowrich and two for Kieran Powell at first slip, with Holder taking three wickets in nine balls.
But Brodrick made the most of a bad drop by Chase when he was on 39 to compile a half-century before he charged Chase in his first over and was stumped.
After Tony Palladino clipped Chase to midwicket and Matt Sonczak edged Roach to slip, Holder chose not to enforce the follow-on which allowed his batsmen more experience of playing under the floodlights against the pink ball.
Brathwaite faced 43 balls before he drove loosely at James Taylor and was taken low down at gully to give the 16-year-old seamer his maiden first-class wicket, but Powell added an unbeaten 41 to his first-innings 92.