Derbyshire 398 for 9 (du Plooy 103, Reece 77) lead Gloucestershire 377 (O Price 132, Dal 6-69) by 21 runs

The 28-year-old South African was 103 not out at stumps, taking his run tally in the competition this summer to 1,155 at an average of 88.84, as his side posted 398 for 9 from an overnight 262 for 6 in reply to Gloucestershire 377.

Unbeaten on 44 at the start of play, du Plooy's innings extended to four hours on a slow pitch. He faced 154 deliveries and struck 13 fours. Left-arm spinner Zafar Gohar was the most successful of the home bowlers with four for 121 from 38 overs.

Persistent rain throughout the morning delayed the start. An early lunch taken at noon, with a view to a 12.40pm start, but it was a further half hour before conditions were deemed playable.

A day in which 104 overs were due to be bowled saw the number reduced to 72. With five until the second new ball, Gloucestershire opened with spin at both ends, but neither Gohar nor debutant Ed Middleton was able to engineer a breakthrough.

A single off Gohar took du Plooy, unbeaten on 44 overnight, to his sixth Championship half-century of the summer, off 81 balls, with 7 fours. The new ball was taken at 272 for 6, but made little initial impact as Anuj Dal supported his skipper with a valuable innings of 21.

It ended with the reintroduction of Gohar and a delivery which appeared to keep a little low in piercing Dall's defence and bowling him between bat and pad. At 292 for 7, Derbyshire trailed by 85 and required another meaningful partnership.

Alex Thomson helped du Plooy supply it with an impressive contribution for a player with a highest first class score of 54. He contributed 34 from 65 balls to an eighth-wicket stand of 65 in 15 overs that took the total to 357.

Having hit 5 meaty fours and handled the short ball well, Thomson miscued an attempted pull shot and was on his way back to the pavilion before Miles Hammond pouched a straightforward catch.

The unflappable du Plooy then found another reliable partner in Mark Watt as they closed the remaining 20-run deficit of their opponents' first innings score. It was the captain who put his side in front with a swept single off Gohar.

By tea, the pair had taken the score to 388 for 8 off 108 overs, with two more to notch the 12 runs necessary for a fourth batting point. Unbeaten on 97, du Plooy needed just two deliveries after the break to loft offspinner Ollie Price over mid-on for his 13th four and a hundred off 151 balls.

Two balls into the second over after tea light rain started falling and the players left the field with the scoreboard reading 394 for eight. Nine more overs were lost before the resumption saw Watt cover drive Middleton for four.

Derbyshire needed two runs off the final ball of the over for the extra batting point. But Middleton kept his cool and registered his maiden first class wicket when Watt gave him the charge and was stumped by James Bracey yards out of his crease.

Watt left the pitch thumping his pad in frustration, which must have grown when the umpires took the players off again, this time for bad light, without another ball bowled. Gloucestershire at least had the consolation of a third bowling point, courtesy of their young legspinner. More rain began falling and umpires Tom Lungley and Jack Shantry abandoned play for the day at 5.25pm.