The League One Seasiders had gone ahead through Danny Philliskirk's 62nd-minute opener but substitutes Blair Turgott and Holman turned the game on its head to send the National League outfit through.
Matt Patterson, who caused a stir on social media over the summer when he was pictured signing his contract in a McDonald's, scored Oxford's goal in 1-0 victory while Delano Sam-Yorke bagged a brace before being sent off in Maidstone's thrilling 4-2 victory at Cheltenham.
Slough were convincing 6-0 winners at National League North side Gainsborough, with Matt Lench scoring a hat-trick for the visitors.
Shaw Lane, another in the seventh tier, were unable to join them in the next round having lost 3-1 to Mansfield earlier in the day, but Southern League Premier Division club Hereford made it through by beating AFC Telford United 1-0.
Wigan and Blackburn, who were both Premier League clubs earlier this decade, had to come from behind to see off Crawley and Barnet and fellow League One club Peterborough could only draw 1-1 with Tranmere.
AFC Fylde and Gateshead, who play in the fifth tier, advanced courtesy of victories over Kidderminster and Chelmsford, while League Two clubs Forest Green and Morecambe negotiated their way past Macclesfield and Hartlepool.
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