Bettencourt and Wilson (69) were at 9-under 207 and shared a one-stroke lead over second-round co-leaders Jim Furyk and Jonathan Byrd. Both had 71s and are tied for third at 208.
World No. 1 Tiger Woods was tied for seventh at 211 after a 68 Saturday.
"Overall I got myself back in the tournament. I've got a shot tomorrow," said Woods, who won three straight Memorial titles from 1999-2001.
Bettencourt, a 34-year-old Tour rookie, has just one top-25 finish in his 16 starts this season.
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