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Phrase(s): beat the clock
Fig. to do something before a deadline; to finish before the time is up. (Alludes to accomplishing something before a clock reaches a specific time.) • Sam beat the clock, arriving a few minutes before the doors were locked. • They were afraid they would be late and hurried in order to beat the clock.
McGrawhill's American Idioms And Phrasal Verbs
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Finish something or succeed before time is up, as in The paper went to press at five o'clock, and they hurried to beat the clock. The term comes from various sports or races in which contestants compete within a certain time limit.
American Heritage Idioms