Something must give at Narberth tomorrow evening when the two unbeaten sides in the WRU Age Grade under 20 Championship meet head on in Narberth.
The Scarlets, who were deserved 24-7 winners at the Ospreys in their opening game of this season's competition, will be looking to use home advantage when they meet the Dragons.
The visitors kicked off their season with a 13-12 home success against the Blues, but will find this an altogether tougher assignment, in west Wales.
The other game sees the Ospreys travel to Glamorgan Wanderers to face the Blues.
Scott Andrews, who scored one of the Blues' consolation tries last week, starts as captain, whilst in the Dragons' side, senior full back Jason Tovey is included.
Cardiff Blues: J Loxton; L Fear, H Allen, D Gunter, R Healey; J Murphy, G Lucas; T Price, R Williams, S Andrews (capt), N Huntley, D Partridge, K Dacey, J Thomas, B Morgan. Replacements: M Howells, B Lee, J Navidi, S Studley, T Rowlands, R Locke, J Deacon
Scarlets: D Newton; J Davies, S Soul, S Williams, N Davies; D Etteridge, T James (capt); O Evans, L Lewis, S Gardner, J Davey, S Jones, E Lloyd, J Davies, R Decapenter.
Replacements: A Howells, G Flynn, L Kendall, H Boot, G Davies, N Reynolds, M Evans
Dragons: J Tovey; O Halford, A Hughes, M Pewtner, N Preece; D Langdon, D Jones; D Watchurst, C Fillier, S Maguire, S Pailor, A Sweet (capt), M Allen, R Jenkins, J Thomas. Replacements: A Coundley. R Price, L Bray, T Falatau, C Davies, I Coombs, T Driver