Leicestershire 96 (van der Gugten 5-52) and 78 for 0 trail Glamorgan 199 (Carlson 74*. McKay 3-12, Dexter 3-36) by 25 runs
An extraordinary opening day's cricket on which 20 wickets fell and 373 runs were scored ended with Leicestershire and Glamorgan on something close to even terms in their Specsavers County Championship Division Two match at Grace Road.
Glamorgan skipper Jacques Rudolph exercised the away team's right to bowl first, a decision based on atmospheric conditions rather than the appearance of the pitch, and there were no signs of the carnage to come as Leicestershire recovered from the early loss of Angus Robson, caught at third slip off the bowling of Michael Hogan.
Paul Horton and Neil Dexter looked in control before Dexter, unluckily, was bowled off the inside edge trying to force a wide delivery from Craig Meschede through the off side. Horton was then given leg before to a Timm van der Gugten inswinger, and the procession continued when both Ned Eckersley and then Mark Pettini were caught behind off successive balls throwing the bat at wide deliveries.
The in-form Mark Cosgrove went caught and bowled off the leading edge, van der Gugten throwing himself to his right to scoop up the ball one-handed just before it hit the pitch, and the seamer picked up a five-for by bowling Harry Dearden, the young left-hander looking to drive an inswinger that took the inside edge and knocked back his leg stump.
Ben Raine lofted a delivery from Lukas Carey straight to mid-off, Dieter Klein was palpably leg before to the same bowler, and it took an innings-best and lunch-delaying partnership of 32 between Charlie Shreck, who made a season's best score of 20, and Clint McKay for Leicestershire to get anywhere near three figures.
Having been dismissed for 96, Leicestershire took six wickets in the afternoon session to keep themselves in the match, with allrounder Dexter picking up three victims in four overs shortly before the break.
Rudolph was the first to go after lunch, bowled by McKay with an inswinger delivered from around the wicket. Will Bragg and Nick Selman added 47 for the second wicket, but both fell with the score on 63, Bragg caught behind fencing at a Shreck delivery and Selman edging a flat-footed push to Horton at first slip off Raine.
Youngsters Aneurin Donald and Kiran Carlson compiled a partnership of 61 in 8.4 overs for the fourth wicket, driving a series of half-volleys through the off side before Donald, again driving airily, was bowled through the gate for 32, hit off just 23 balls.
Meschede and Mark Wallace were both caught behind off Dexter outswingers, the former looking to drive, the latter to defend, and the first over after tea saw Klein blast out Owen Morgan and van der Gugten with quick inswingers. The 18-year-old Carlson continued to play without fear, however, reaching 74 off just 74 balls and hitting 12 fours before he ran out of partners.
When Leicestershire went back in the conditions were put into context when Robson and Horton compiled an unbroken opening partnership of 78 to leave them 25 behind at the close.