County Championship D1, The Oval, day one (close): Surrey 401-8 v Sussex
Surrey's Graham Thorpe pressed his England claims with a second century in two innings at The Oval.
Thorpe, who hit a ton against Somerset in Sunday's C&G Trophy victory, scored 156 to give the reigning champions the clear edge.
Ali Brown (74) and Adam Hollioake also made valid contributions, the Surrey skipper falling for 77 just before stumps.
Early strikes to James Kirtley and Billy Taylor reduced Surrey to 22-2 early on.
But Thorpe combined with Mark Ramprakash (37), Brown and Hollioake to gradually wrest the initiative off Sussex.
Thorpe's knock, which boasted 26 boundaries, was brought to a close when he was caught behind off Mushtaq Ahmed.
Kirtley bagged his third wicket, removing Azhar Mahmood for a duck, soon after as Sussex mounted a late comeback.
Surrey: I J Ward, J N Batty (Wkt), M R Ramprakash, G P Thorpe, A D Brown, A J Hollioake (Capt), Azhar Mahmood, M P Bicknell, I D K Salisbury, Saqlain Mushtaq, J Ormond.
Sussex: R R Montgomerie, M W Goodwin, C J Adams (Capt), T R Ambrose, R S C Martin-Jenkins, M H Yardy, M J Prior (Wkt), K J Innes, Mushtaq Ahmed, R J Kirtley, B V Taylor.