United trailed 2-0 at half-time at Leeds Trinity University – but reduced the deficit to 2-1 and 4-2 in the second half.
Krisztian Gagyi and JJ Ward scored the United goals.
Boston (3-4-2-1): Jake Lovelace (Cameron Fox 46); Taylor Redman (Lucas Stubbs 68), Owen Sheriff, Taylor Jaine; JJ Ward, Will Langford (Rueben Fogg 46), Jake Henderson, Josh Doran (Oskar Rajski 61); Han Stevens, Lucas Turrell (Callum Pratt 61); Krisztian Gagyi.