They also claimed victory over regional rivals Llanelli in a midweek fixture, that win perhaps the most impressive of the four so far this season. Their latest win, a defeat of Swansea at St. Helen's, means Tonkin's side will be full of confidence as they welcome the Keys.
Last season, the Quins won a dour encounter between the two sides in early November. Jason Harries scored the only try in a 14-3 win with James Dixon kicking three penalties. Keys could only manage a first half penalty from Dorian Jones in a match that certainly did not live long in the memory.
In the return fixture at Pandy Park on the final day of last season, Keys had their revenge, easing to a 28-3 win with Kristian Baller crossing twice and Nathan Trowbridge and Scott Matthews also scoring.
With a trip to second placed Quins on the horizon, Keys know they will need to be on top of their game to take anything from this game. Head coach Greg Woods has made no fewer than 10 changes to the side that defeated Llandovery last time out.
It's certainly a bit of a gamble but with their British & Irish Cup campaign beginning next weekend, Woods is certainly using the depth of his squad.
Quins are much more settled but are without Wales Sevens internationals Iolo Evans, James Davies and Lee Williams. Jason Harries is available though with Haydn Pugh and young Carwyn Jones continuing what looks an exciting partnership at lock.
Carmarthen Quins: 15 Howard Thomas 14 Pan Rushesha 13 Dylan Morgans 12 John Rhys Williams 11 Jason Harries 10 Aled Thomas 9 Rhodri Michael Wells, 1 Gareth Thomas 2 Rhodri Clancy 3 Ian Jones (c) 4 Carwyn Jones 5 Haydn Pugh 6 William Boyde 7 Elis Lloyd 8 Sion Bennett.
Replacements: Gethin Robinson, Ryan Elias, Javan Sebastian, Aidan Laxton, Rory Gallagher, Christopher Banfield, Rhys Thomas, Craig Evans.
Cross Keys: 15 Aaron Bramwell 14 Nathan Williams 13 Luke Williams 12 Phil Williams 11 James Cordy-Redden 10 Dorian Jones 9 Ryan James, 1 Richard Cornock 2 Gerwyn Price 3 Anthony Lott 4 Danny Hodge 5 Ollie Hodge 6 Jevon Groves 7 Rhys Peebles 8 Adam Powell (c).
Replacements: Luke Garrett, Darren Hughes, Tom Lampard, Reuben Tucker, Rhys Dyer, Angus O'Brien, Nathan Trowbridge, Ciaran Driscoll.