Hill was one of a raft of late improvements in the opening session, which took place amid light drizzle, and steered his West Surrey Racing-run BMW 330e M Sport around the Indy Circuit 0.097 seconds quicker than the Motorbase Performance Ford Focus ST of three-time champion Ash Sutton.
Apart from a few people bedding in wet-weather rubber, the competitors ran on slick tyres throughout, and the majority took the opportunity to put a heat cycle through the soft-compound Goodyear as option tyres return to the series after a season away this weekend.
