|LV= County Championship Division Two, Bristol (day two)|
|Gloucestershire 275: Roderick 76, Footitt 3-72|
|Derbyshire 511-8: Guptill 227, Thakor 83, Taylor 5-89|
|Derbyshire lead by 236 runs|
|Gloucestershire 4 pts, Derbyshire 8 pts|
Martin Guptill smashed an impressive double century to put Derbyshire in an excellent position on day two against Gloucestershire at Bristol.
The New Zealand batsman struck 29 fours and 11 sixes in a destructive 227 as he and Shiv Thakor (83) scored quickly to help establish a 236-run lead.
Openers Ben Slater (56) and Billy Godleman (44) set the platform before Liam Norwell (2-107) removed them both.
The visitors continued to accelerate in the final session to end on 511-8.
|A powerful partnership|
|Guptill and Thakor added 190 runs at a run rate of 6.26 an over to take Derbyshire from 191-4 to 381-5|
Gloucestershire were guilty of dropping catches with Slater reprieved from the first ball of the day, before Guptill offered a straightforward chance to Geraint Jones at slip when on 57 and Will Tavare at point on 101.
He punished the home side's profligacy, reaching a career-best first-class innings, with three consecutive sixes off Norwell.
The 28-year-old was eventually caught off the bowling of Matt Taylor (5-89), but his efforts helped Derbyshire pile up 487 runs in the day, with youngster Harvey Hosein weighing in with an unbeaten 43 before the close.
Gloucestershire captain Geraint Jones:
"It was an international quality knock by Guptill and pretty much a one-day innings. He assessed that others were getting nicks and opted to go on the attack.
"That is what top batsman do. He seized on anything wide or short and we failed to stick to the off stump line we wanted to bowl, dishing him up a lot of cuts and pulls.
"We work so hard on our fielding so it's hard to explain why so many catches are going down."
Derbyshire batsman Martin Guptill:
"It was the sort of pitch where I thought if I tried to bat time I would get a nick, so I decided to go for it. When you take that approach you need a bit of luck and I had some today.
"When the second new ball was taken I started trying to hit everything out of the park. It was harder, so it came off the bat better.
"It's taken me quite a few games to hit a first class double hundred. I got stranded on 195 a few years ago for Auckland and it's nice to have reached the landmark."