Great article from James Pearce in The Athletic detailing how Jürgen and staff managed the turnaround from late Wednesday night in Istanbul to Saturday afternoon at Southampton.
The sport science part is obviously huge, with the squad members who didn't play going through a core session at their hotel early Thursday morning, a NASA-developed ice pack being used during the flight home. Psychology comes into it as Jürgen talked to the team about not being interested in excuses despite himself being unhappy that the Saturday match wasn't moved back a day.
The team had just an hour's training Friday plus a short video session where they went over Southampton's strengths and weaknesses, plus set piece tendencies (coaching staff had studied this and devised a plan during the flight back and after). Nutrition and rest were also preached but care was made to not overload the players with information during the short turnaround. The group flew that evening to Southampton, had a meal and went to bed, with physios working on Adrian's ankle all the while. Saturday morning the team went on a group walk, and then the match.
The main halftime adjustment was to get the fullbacks and midfielders more involved in attack. The limitations to this were evident given how tired everyone was, but the difference was evident for 25-30 minutes, which along with the brilliance of the two goals, was enough.
Players were given Sunday and Monday off and then they'll be back at it tomorrow, with 3-4 days proper training for Arsenal and, I predict, a top drawer performance and three points.