Phil Jaques and Alex Lees both scored big centuries as Yorkshire dominated day one against Derbyshire at Chesterfield.
Opener Lees was unbeaten on 171 while former Australia international Jaques made 139 as the visitors reached stumps on 367-2 after winning the toss and opting to bat first.
The duo put on a record second-wicket stand worth 311 following the early loss of Adam Lyth, who was caught behind by wicketkeeper Tom Poynton off the bowling of Mark Footitt for 10.
From then on, though, Division One's basement boys were made to suffer; Mark Turner came in for some particularly heavy punishment, his 12 overs going for 86 runs.
Off-spinner Peter Burgoyne did impress on his Championship debut and was unlucky not to take a wicket during 33 overs of hard work on a scorching day.
Lees celebrated signing a new contract by hitting a career-best score, winning the race to reach three figures as he helped add 134 runs in the afternoon session.
Jaques, who had looked a little anxious at the start of his innings before becoming increasingly assured, reached his first ton of the first-class season from 174 deliveries.
The highest ever second wicket partnership at the Queen's Park venue finally came to an end at the start of the 88th over when Jaques steered Tim Groenewald to first slip.
However Derbyshire could find no way of moving Lees, the 20-year-old showing just why Yorkshire have handed him a deal that will until December 2015 with his second century of the summer.