The title looks to be between Alan Solomon's side, the Scarlets and Gwent Dragons, and the Dragons can effectively kill off the challenge of Celtic Warriors who they play this evening at Rodney Parade (7pm).
Elsewhere, Leinster Lions entertain The Borders at Donnybrook (7.30) and the presence in the city of Scotland supporters should ensure a big crowd.
Munster are in Glasgow hoping to avoid a fourth successive defeat and Connacht are also away, in Wales to play second placed Llanelli Scarlets .
Connacht: M Mostyn; C McPhillips, D Yapp (capt), M McHugh, W Munn; E Elwood, M Walls; D McFarland, B Jackman, A Clarke, D Browne, A Farley, P Neville, M Lacey, J O'Sullivan. Replacements: J Fogarty, P Bracken, M Swift, T Carter, C O'Loughlin, S Moore, J Meagher.
Ulster: B Cunningham; J Topping; S Stewart, P Steinmetz, T Howe; A Larkin, K Campbell; S Best, M Sexton, R Moore, R Frost, M McCullough, N McMillan, A Ward (capt), N Best. Replacements: P Shields, R McCormack, G Longwell, N Doak, P Wallace, S Young, W Brosnihan
Munster: S Payne; J Kelly, R Henderson, M McPhail, M Lawlor; J Holland, E Reddan; F Roche, J Flannery, G McIlwham, T Hogan, D Pusey, E Halvey, C McMahon, J Williams (capt). Replacements (from): Barry Murphy, C O'Sullivan, Frank Murphy, P Malone, S Keogh, R Callaghan, M Cahill, J Danaher.
Leinster Lions: J Norton; J McWeeney, G Brown, C Warner, B Burke; F Contepomi, B O'Meara; J Lyne, D Blaney, P Coyle, C Potts, B Gissing, A McCullen, N Ronan, D Dillon (capt). Replacements: S Brophy/J Moran, B Blaney, A Kearney, S Crawford, B O'Riordan, M Leek, J Downey.