Raymond van Barneveld upset Gerwyn Price in a thrilling 5-4 win to reach the Grand Slam of Darts knockout stages in Wolverhampton.Van Barneveld, 55, recovered from 3-1 down to book his place in the last 16, despite world number one Price throwing a 106 average.Three-time champion Price must now beat 2014 winner Dave Chisnall in his final Group A match on Monday to progress.Dirk van Duijvenbode, Wales' Jonny Clayton, Michael van Gerwen and Luke Humphries all qualified for the knockout phase, but Fallon Sherrock and Lisa Ashton had their hopes dashed.Van Duijvenbode recovered from 3-1 down to beat Rob Cross 5-3 in Group D, Clayton progressed from Group F after whitewashing Jermaine Wattimena 5-0 and Van Gerwen made it back-to-back wins in Group G by beating Luke Woodhouse.Humphries produced the highest average of the tournament so far - 107.4 - in an impressive 5-1 win over Ryan Searle.Sherrock won the opening leg in her 5-1 Group E defeat to Nathan Aspinall and Ashton lost 5-2 to Group C rival Ritchie Edhouse.World champion Peter Wright scraped to his second Group E win, but only after Alan Soutar missed six match darts in the deciding leg to lose 5-4.Michael Smith took control of Group C with a 5-1 win over Joe Cullen and Danny Noppert made it successive wins in Group B by defeating Simon Whitlock 5-2.Josh Rock and Damon Heta both secured 5-4 wins against Scott Williams and American Leonard Gates respectively and Ross Smith defeated Nathan Rafferty 5-2.