Pakistan opener Shan Masood on Friday hit a second successive double century in the English county championship to take his aggregate to 608 runs in four innings.
The 32-year-old was out for 219, having hit 24 fours and a six as Derbyshire racked up 401 runs in the day to reach 437 for four and lead by 224 in their game against Leicestershire.
Masood's magnificent innings followed his 239 in last week's draw against Sussex.
Left-arm spinner Callum Parkinson finally claimed Masood's wicket on Friday, bowling him with a ball that turned sharply from outside the left-hander's off stump.
"If we are to do well, we need to make the big hundreds," said Masood.
"To get two double hundreds is pleasing. Making it big is always something we talk about."
Masood turned for the pavilion when he was out but could leave the field only after every Leicestershire player, led by Parkinson, had offered a handshake of congratulation on a superb exhibition of high-class batting.
Fellow Pakistan star Shaheen Shah Afridi helped steer Middlesex closer to victory over Glamorgan on his debut.
Afridi dismissed Australian Test player Marnus Labuschagne for the second time in Cardiff to take his fourth wicket of the match.
He also hit a career best 29 as Middlesex made 336 in reply to Glamorgan's 122 all out.
At stumps, the Welsh county were 104-6 in their second innings, still 110 runs behind.
