The Barbarians scored 14 tries in their 84-10 victory, with former Wales' skipper Gareth Thomas leading the way with four touchdowns.
Before the match Barbarians' president Micky Steele-Bodger presented Dany Roelands of the Belgium Federation with a cheque for 10,000 Euros, from the Barbarians Rugby Charitable Trust, to aid development of the game at youth level.
Thomas claimed one first half try and a second half hat - trick with Molitika also claiming a touchdown after the break.
Sunday's team for the Gartmore Challenge will be led by Bristol hooker Mark Regan, who is aiming to complete a unique double at the home of English rugby following the Baa Baas win against the Springboks at the same venue in November.
Regan said,"I am looking forward to this weekend's match tremendously. This Baa-Baas' squad has been together for over a week and our weekend in Brussels and then nearer home in Cheltenham has been a great success. We were obviously disappointed with our defeat against Ireland a couple of days ago but we are working really hard to put on a much better performance against England."
Regan is one of four Englishmen in the Barbarians' match day squad and he also has alongside him three other members of the pack that shocked the Springboks - Italian prop Federico Pucciariello, Wallaby lock Justin Harrison, and All Black flanker Jerry Collins.
The results of two late fitness tests on Stephen Larkham and Maama Molitika will decide the starting line-up with Glen Jackson and David Croft on stand-by.
The Gartmore Challenge will be the eighth meeting between the sides with the Barbarians currently ahead 4-3 in the series.
Team: Thinus Delport (South Africa); Iain Balshaw (England), Morgan Turinui (Australia), Seilala Mapusua (Samoa), Gareth Thomas (Wales); Stephen Larkham (Australia), Andy Gomersall (England); Federico Puciariello (Italy), Mark Regan, captain (England), Cobus Visagie (South Africa), Kris Chesney (Saracens), Justin Harrison (Australia), Jerry Collins (New Zealand), Pedrie Wannenburg (South Africa), Maama Molitika (Tonga)
Replacements from: Sebastien Bruno (France), Patrice Collazo (France), Santiago Dellape (Italy), David Croft (Australia), Mitch Chapman (Brumbies), Michael Claassens (South Africa), Glen Jackson (Saracens), Jaco Pretorius (South Africa)