Trevor Christie, the former Notts County forward, ensured Walsall qualified for the second division play-off finals against Bristol City despite being held to a 1-1 draw at Fellows Park.
Yates, the defender who scored for County on Sunday, repeated the feat with a header in the twelfth minute after Birtles flicked on a centre from Mills to reduce the deficit. But Christie scored his tenth goal of the season in the sixtieth minute to wrap up a 4-2 aggregate score.
McCarthy, who scored in the first leg, also did so in the second, helping Swansea keep alive their hopes of promotion to the third division, with a 1-1 draw at Rotherham.
His goal, from a volley after 19 minutes, gave Swansea a 2-1 aggregate win. Rotherham kept their hopes alive a minute before the break through Johnson, but despite intense second-half pressure, the home side returned to the fourth division for the first time since 1975.
A goal scored against the run of play gave Torquay a 1-1 draw against Scunthorpe and a place in the play-off final against Swansea. Loram scored the decisive goal from Dobson's pass. Scunthorpe's only reward was a penalty goal by Lister after 81 minutes but Torquay went through 3-2 on aggregate - a far cry from last season when they were just minutes away from being relegated from the League. Copyright (C) The Times, 1988