Second row Martin Wolfenden makes his full debut after coming off the bench in the closing stages of the game at Plymouth, while in the backs Dom Lespierre and Callum MacBurnie step up from the bench, George Worth returns at centre and Gaston Mieres
moves to the wing with Scott Hamilton coming in at full-back.
Cov were coming under pressure in the set scrum but, with Richmond centre Cameron Mitchell in the sin bin, they pulled back to level terms after 29 minutes when Gaston Mieres
created space for Matt Price to charge over in the right corner, Cliffie Hodgson adding the conversion from close to the touchline.
Top-ranked players lived up to form as Carlos Daniel Gutierrez and Juan Mieres
Petruf became the first of the men into the semi-finals at the inaugural Dubai Padel Masters at the Nad Al Sheba (NAS) Sports Complex on Thursday.
Worcester: Tries: D Hammond, B Howard, I Mieres
; Cons: Mieres
(3); Pen: Mieres
Dean Hammond sent the home side on their way with a try inside the first minute before Ben Howard and Ignacio Mieres
went over to give Worcester a 21-3 lead.
But Warriors fought back in the second period with scores for skipper JB Bruzulier and replacement scrum-half Charlie Mulchrone, aided by conversions from the boot of Ignacio Mieres
After Ignacio Mieres
' penalty early on, normal service was resumed for the club with the third worst losing sequence in Premiership history, as the visitors ran in four first-half tries in just 20 minutes.
Twelvetrees' strikes, against two from Worcester fly-half Ignacio Mieres
, were all the sides could muster in a match delayed for 30 minutes in bizarre circumstances.
In the opening moments of the second half Worcester's Mieres
hit a penalty from 22 metres which just about cleared the crossbar.
Worcester's points came via a try and conversion from fly-half Ignacio Mieres
and a penalty by Chris Pennell.
kicked that, to add to two earlier penalties.