Mark Ramprakash's unbeaten 142 at just better than a run a ball set up Surrey's 16-run victory over Sussex in the Friends Provident Trophy at Hove.
The ex-England batsman, 37, guided the visitors to a challenging 281-7.
While Murray Goodwin (86) was at the crease Sussex had a chance, but when he holed out to Rikki Clarke off Azhar Mahmood their chances went with him.
Chris Schofield picked up four late wickets with his leg-spin to seal victory for Surrey.
They go third in the South Division table while champions Sussex, who have won only one game out of five, are now unlikely to make the last four.
Ramprakash scored 266 in the Championship at Hove last week and he continued in the same vein under lights on the south coast, recording his seventh ton of the season and his 13th domestic one-day century.
With one leg-side boundary measuring only 60 yards, nine sixes were hit in Surrey's innings, with two balls lost outside the ground.
Ramprakash lost one of them when he swatted paceman Rana Naved over mid-wicket.
He also hit the biggest six of the day when he sent a Luke Wright long-hop soaring into the neighbouring flats.
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