Garner played the full 90 minutes as Nottingham Forest travelled to Sheffield United for a Championship clash.
Jack Colback opened the scoring for Forest after just 10 minutes, before Brennan Johnson added a second goal midway through the second half.
The Blades managed to pull one back in injury time, thanks to midfielder Sander Berge, but Forest will take the advantage of a 2-1 lead going into Tuesday’s second leg at their City Ground.
Later on Saturday, Reds goalkeeper Bishop was also fully involved as Mansfield Town overcame Northampton Town to win 2-1 in the first leg of their League Two play-off semi-final.