Leicestershire 180 for 4 (Cosgrove 67) trail Worcestershire 553 for 6 dec (Rutherford 123, Mitchell 114, Cox 100*) by 373 runs
Acting captain Ben Cox became the third centurion of the innings as Worcestershire built a formidable first-innings score before declaring on the second day of their Specsavers County Championship match against Leicestershire at the Fischer County Ground.
The visitors then picked up four wickets, including the vital one of Mark Cosgrove, leaving the Foxes still needing another 224 runs to avoid the follow-on with six wickets in hand at the close of play.
Resuming on 348 for 4, the visitors quickly lost Hamish Rutherford, the New Zealander adding only seven runs to his overnight score of 116 before driving at a delivery from Tom Taylor and edging a catch to wicketkeeper Lewis Hill.
Taylor, who had two chances dropped off his bowling on the first day, saw another spilled when Will Davis could not hold a Ross Whitely drive chest-high in the covers.
Whitely, on 18 at the time, went on to 49 before an in-swinging yorker from Ben Mike both knocked the left-hander off his feet and dismissed him leg before wicket, but Cox, in company with Ed Barnard, took full toll of a tiring Leicestershire attack.
The pair added 145 for the seventh wicket, with Cox reaching his hundred off 133 balls to join Rutherford and Daryl Mitchell in going to three figures before declaring.
The last time Worcestershire had three centurions in an innings was in 2007, against Surrey at New Road.
Leicestershire suffered an early double blow when captain Paul Horton was caught at second slip driving loosely at Josh Tongue, and Hassan Azad fell leg before to Charlie Morris to leave them struggling on 24 for 2.
They were grateful to Cosgrove, whose belligerent counter-attack saw him hit eight boundaries in the space of nine deliveries from Wayne Parnell.
At the other end Javid was dropped twice by Tom Fell at third slip, on 1 off the bowling of Tongue and on 22 off Ed Barnard, and he and Cosgrove went on to add 111 for the third wicket before Cosgrove drove loosely at Barnard, failed to keep the ball down, and saw Brett D'Oliveira take a fine low catch at cover.
Tongue then bowled Colin Ackermann off the inside edge to ensure Worcestershire finished the day in a strong position to enforce an innings victory.