|Bob Willis Trophy, Emerald Headingley (day one):|
|Yorkshire 280-4: Malan 145*, Tattersall 64*|
|Derbyshire: Yet to bat|
|Yorkshire 2 pts, Derbyshire 1 pt|
Dawid Malan scored a superb unbeaten maiden Yorkshire century as the hosts had much the better of day one against Derbyshire.
Both sides have won their opening two North Group games, with Derbyshire leading the race for top spot by four points.
However the visitors, missing the experience of Luis Reece, Ravi Rampaul and Tony Palladino, were unable to capitalise on a couple of openings having won the toss and elected to bowl under grey skies.
Yorkshire fell to 40-2 and 106-4 either side of lunch before closing on 280-4.
On the England left-hander's home debut following his winter move from Middlesex, Malan finished on 145 not out from 180 balls and Jonny Tattersall unbeaten on 64 from 142 after bad light ended play early.
Malan's England team-mate Jonny Bairstow - in their last four-day group appearance if either win national limited-overs selection against Pakistan and Australia - made 22 having been dropped on nought.
The feature of Malan's knock was his dominant driving, both through the covers and down the ground as he shared a third-wicket partnership of 66 with Adam Lyth (31), then an unbroken fifth-wicket stand of 174 inside 44 overs with a quieter Tattersall.
He hit a friendly half-century here against Durham last month before a match-clinching 73 came against the same opponents at Emirates Riverside in the opening round of this competition.
It was a helter-skelter start to proceedings under the Headingley floodlights - which remained on all day.
Ben Aitchison had Tom Kohler-Cadmore caught at third slip for a duck, off an under-edge as he tried to leave alone, leaving Yorkshire at 2-1 in the second over.
In the third, Lyth then pulled South African left-armer Michael Cohen for back-to-back sixes before Bairstow was dropped on nought by Derbyshire captain Billy Godleman at mid-off following an uppish drive at Dustin Melton.
Bairstow went on to drive three boundaries - two particularly convincing either side of mid-off - and pull another before he pushed aggressively at seamer Anuj Dal and edged behind.
That brought Malan to the crease and he added 66 with Lyth until early afternoon before Cohen returned to remove Lyth (31) and Harry Brook (0) within the space of four balls.
But Malan remained in serene touch as he set about his 26th first-class century. He reached his fifty off 87 balls, then his ton off 136, by which time Yorkshire had gone beyond 200 for a first batting bonus point.
The century stand between Malan and Tattersall - playing as a specialist batsman, with Bairstow taking the wicketkeeping gloves - had also been confirmed.
Tattersall's innings was understated but a crucial foil for Malan, who later lofted Matt Critchley for six over long-off.
Tattersall accumulated and worked the ball well on the way to a 122-ball fifty and will hope to convert that into a maiden first-class century against county opposition at the start of day two.
Yorkshire's Jonny Tattersall:
"We're really pleased with how it's gone, and Dawid's obviously shown his class there and gone through the gears.
"I played second fiddle and was trying to give him the strike and keep ticking over. He's so easy to bat with, and it takes the pressure off me.
"We really grinded them into the dirt, and hopefully we can do the same."
Derbyshire captain Billy Godleman:
"Having won the toss and had some helpful conditions we're just behind at the moment. But that's through no fault and lack of endeavour from the guys.
"In the first two sessions in particular, I thought they wheeled away excellently.
"If a good player gets in like Dawid and scores a chanceless hundred, occasionally you can say 'well played'.
"I'm still happy with the decision to bowl first - even more so having seen how the wicket played, particularly in the first two sessions."
Report supplied by PA Media.