The Open cut explained: How many players make the weekend at Royal Birkdale?

The battle to make the weekend is well underway at the 154th Open Championship after the opening round at Royal Birkdale.

American debutant Jackson Suber leads the field on five-under par after an outstanding opening 65, but with another 18 holes to play before the cut, plenty of the game's biggest names still have work to do.

What is the cut at The Open?

The Open Championship cuts the field to the top 70 players and ties after 36 holes.

There is no 10-shot rule, so only a place inside the top 70 and ties at the end of Friday's second round will earn players a place in the weekend field.

The format matches the PGA Championship, while the Masters cuts to the top 50 and ties and the U.S. Open to the top 60 and ties.

Where is the cut line?

As things stand after Thursday's opening round, the projected cut line is one-over par.

Data Golf's live model, however, believes the cut is more likely to move to two-over par by the end of Friday, although one-over par remains a realistic possibility depending on scoring conditions.

The Open LIVE Leaderboard

Big names with work to do

Rory McIlroy is among the headline names currently outside the projected cut after an opening two-over 72, leaving the Masters champion needing a strong second round to avoid an early exit.

Jordan Spieth, Cameron Smith, Brian Harman, Justin Rose and Joaquin Niemann also begin Friday on the wrong side of the projected cut line.

Defending champion Scottie Scheffler is in far healthier shape after opening with a two-under 68 as he looks to become the first player since Padraig Harrington in 2008 to successfully defend the Claret Jug.

Recent Open Championship cut marks