Complex sentence: During this period rivalry between the two clubs was intense, in the 1889 FA Cup Scarborough knocked Whitby out in the First Round, with Whitby complaining that Scarborough's ground was an illegal size.
Split into simpler sentences: During this period rivalry between the two clubs was intense. In the 1889 FA Cup Scarborough knocked Whitby out in the First Round, with Whitby complaining that Scarborough's ground was an illegal size.