If you do something against the clock, you do it as fast as possible and try to finish it before a specific time.

For example:

• We’re working against the clock to finish this project before the deadline.

• The emergency services were working against the clock as the tide began to rise. 

• We left later than we were supposed to, so it was a race 

against the clock to get to the airport on time.

• We’ll have to work against the clock to finish our presentation in time for the convention, but I think we’ll be able to get it done.
• Jen’s going to have to race against the clock if she wants to get her story in tomorrow’s newspaper, it’s almost time to send it to the publisher!

Tradução:

Correndo contra o tempo, contra o relógio.