The Saints suffered a 2-1 defeat to Tottenham away from home at Tottenham Hotspur Stadium in the Premier League.
Southampton took the lead on the half-hour mark when Danny Ings glanced home James Ward-Prowse’s corner.
Gareth Bale, signed on loan from Spanish and European giants Real Madrid in the summer of 2020, restored parity for Spurs on the hour mark when he curled the ball into the back of the net.
Son Heung-min secured the points for Spurs in the 90th minute from the penalty spot.
Hasenhuttl told BBC Sport: “I can’t say we had less energy than on Sunday. We still had a good game but were better today with the ball, we had a clearer plan and we had more movement and more chances.
“In the first half we had chances for three goals and scored one. It’s not enough to score one goal because we always concede one - clean sheets are missing. The way we defended was not good enough.
“We have eight substitutes and normally should be able to replace him [Danny Ings] but today we couldn’t really push our game with the subs and the opponents were stronger.”
Match Stats
Over the course of the 90 minutes at Tottenham Hotspur Stadium on Wednesday evening, hosts Tottenham had 62% of the possession, took 12 shots of which three were on target, and earned five corners.
Visitors Southampton had 38% of the possession, took 10 shots of which five were on target, and earned five corners.