With the Europa League their priority, Postecoglou made eight changes to his side as they ended their three-match losing run in the league.
Only goalkeeper Guglielmo Vicario, Yves Bissouma and Richarlison preserved their places in the starting line-up from the first leg.
«It’s something we’ve been doing for a while because we’ve had to,» the Spurs boss told BBC Sport.
«We’ve had a wretched run with injuries — which still hasn’t eased up, to be fair. But with the opportunity we’ve got before us [in the Europa League], it made sense.»
Archie Gray, Kevin Danso, Ben Davies and Djed Spence featured in a fully changed defence while Mathys Tel and Wilson Odobert, who combined for the 15th-minute opener, made up the front three alongside Richarlison.
Tottenham remain 16th with 38 points from 35 games — one point clear of West Ham and one behind Everton and Manchester United — with three games left.
But Postecoglou said he was proud of his players’ efforts in the derby.
«It’s not easy making so many changes and it’s going to affect the fluency and even the rhythm of the team,» he said.
«I thought the efforts they put in were outstanding. They were disciplined and organised.
«I thought we nullified their threat as well as we could, and they had some decent firepower up front, and I still thought we were dangerous going the other way.»
If Spurs do get past Bodo/Glimt on Thursday, either Manchester United or Athletic Bilbao will await them in the final on 21 May.
Postecoglou’s side are looking to secure the club’s first silverware since 2008 and a place in the Champions League by winning the Europa League.
