[9] He was a member of the team that put up a "splendid display" in the final of the 1903 Durham Senior Cup, taking a two-goal lead against cup-holders Sunderland "A" before "eventually class told" and Eldon lost 3–2.
[12] Daykin joined Football League First Division club Sunderland in March 1905 on amateur forms until the end of the season, at which point he was expected to turn professional.
[13] With Jimmy Watson absent on international duty, Daykin made his debut on 1 April playing at left back at home to Manchester City.
[14] He played no more first-team football that season, but was fit enough by March to be on the winning side for the "A" team against Hebburn Argyle in the 1906 Durham Senior Cup Final,[15] and his services were retained for another year.
He came into the side for a visit to Woolwich Arsenal in early December when Watson was rested, and "played excellently" in a 1–0 win; the Athletic News noted that "even when beaten, he made some remarkable recoveries.
He has usually appeared in the intermediate line, where his abilities as a two-footed player make him useful in either position, but when occasion has demanded he has been a general utility man, both forward and at back.
[25][26] The only fit senior full back, Walter Corbett, who had been in dispute with the club, offered his services after Daykin's injury, but he was unable to play in the next match because the Football Association turned down his request to withdraw from the amateur international on the same day.
[27] Birmingham finished bottom of the Second Division, applied successfully for re-election to the League,[28] and, after a season in which the players pledged wages to an appeal to keep the struggling club afloat,[29] it underwent a complete overhaul both on and off the field.