PDC Youth final runner-up Rowby-John Rodriguez has made an impact on his Grand Slam of Darts debut by taking the scalp of Adrian Lewis.
The Austrian was always in control against the two-time world champion and deservedly ran out a 5-2 winner to leave Lewis requiring wins from his final two group matches.
Michael van Gerwen endured a scare against Darren Webster before prevailing in a last-leg decider, while 2012 winner Raymond van Barneveld made a strong start with a 5-3 success over Robbie Green.
Terry Jenkins made light work of former champion Scott Waites, with fellow BDO representative Jan Dekker also falling to a 5-2 defeat to Kim Huybrechts.
However, there was better fortune for Lakeside runner-up Alan Norris as he saw off Ronny Huybrechts in convincing fashion.
In the afternoon's other matches, Vincent van der Voort beat Robert Thornton while Dave Chisnall recorded a three-figure average in beating Keegan Brown.
Results in full: Kim Huybrechts 5-2 Jan Dekker, Terry Jenkins 5-2 Scott Waites, Vincent van der Voort 5-2 Robert Thornton, Dave Chisnall 5-1 Keegan Brown, Alan Norris 5-2 Ronny Huybrechts, Michael van Gerwen 5-4 Darren Webster, Raymond van Barneveld 5-3 Robbie Green, Rowby-John Rodriguez 5-2 Adrian Lewis