Tony Adams resigned at Wycombe and the U’s sacked Graham Rix during November.
Gorman's first three results were two wins and a draw, Diaz, the former Argentina international who also led River Plate to five league titles in his home country, won one and drew two.
Early results had gone well for both new managers, up until Christmas. Wycombe suffered two defeats and Oxford slipped to a 2-0 reverse at home to bottom side Kidderminster on Bank Holiday Tuesday.
Oxford United winger Chris Hackett said: "We play Wycombe quickly which gives us a chance to put the result behind us."
"It's horrible when you have a week or so to wait until your next match, but we can hopefully put everything right and get a result on Saturday," he added.
Meanwhile at the Moss Rose Stadium on Tuesday, there was drama as Wycombe thought they had grabbed a point when Roger Johnson levelled in injury time - the home side had led since the fifth minute. The Wycombe players and management team celebrated a draw that Gorman felt they had deserved overall. Then Macclesfield scored at the death to win 2-1, which led to ugly scenes involving both managers.
Afterwards Horton made an apology to his opposite number through the press.
"I thought they (Wycombe) over-celebrated and perhaps I did the same in return but it is a very passionate game. I am an old friend of John's and if he wants a beer after the game I'd be delighted to have one," he said.