Alastair Cook turned Essex's Friends Provident Trophy semi-final bash yesterday into a full-scale dress rehearsal for his appearance in Thursday's first Test against South Africa.

No batsman on view before a capacity Chelmsford crowd could have been more acutely aware of the need for runs to set Yorkshire a decent target, but Cook played with such aplomb that his knock could have been mistaken for a Test innings.

In form: England's Alistair Cook

The 23-year-old England opener scored 95 runs off 127 balls without ever allowing his concentration, classic technique and general obduracy in the face of a strong Yorkshire attack to waver from the high standards he sets.

He rarely found it necessary to coax runs through the air, preferring instead to dispatch shots all round the wicket across a fast outfield.

Matthew Hoggard, Darren Gough and Tim Bresnan are strictly second division when compared with the South Africa attack of Dale Steyn, Morne Morkel and Makhaya Ntini he could be facing at Lord's, but the field was tightly set and Cook found the gaps with aplomb.

This should have been Cook's second one-day century for Essex but for the second time in seven days he was dismissed in the nineties, having scored 95 in a championship match against Derbyshire last Sunday. He dominated stands of 61 with Jason Gallian, 21 with Mark Pettini and 98 with Ravi Bopara to show a mounting fluency of strokeplay as his innings progressed.

The square cut he produced off Hoggard for the first boundary of the day, and the sixth off Bresnan that raised his halfcentury were worthy of a Test match audience, but the Essex faithful were more than satisfied with the England-contract player they see all too rarely for their liking.

His innings again questioned the wisdom of England's preference for giving Cook almost guaranteed Test status without backing the cultured shots all round the wicket that make him a formidable one-day opponent at the top of any batting order.

It certainly needed something special to remove him from the crease yesterday, and it came in a direct throw from Bresnan at deep fine leg that ripped out the middle stump, with Cook well short of the crease taking a second run.

He was halfway to the pavilion when the third umpire delivered his judgment with the crowd already applauding an innings of Test quality that helped Essex to 285 for eight from their 50 overs.