Yes. That’s absolutely fine.
You can just join the auction in real-time and bid live.
To do this, click the ‘Bid live now' button and enter the live bidding screen.
When your lot is being sold, you’ll know when your max bid’s working, as you'll see that you're in the lead without clicking anything.
If your max bid is beaten, and you want to continue to try to win the item, you can just bid live by clicking on the 'bid' button up until the point where you win or hit your budget!