The 51-year-old Austrian only took charge of the side on Thursday and he asked Southampton fans to judge his team at the end of the season.
The first hour will have been extremely uncomfortable viewing as Spurs threatened to run riot, leading 3-0 through goals from Harry Kane, Lucas Moura and Heung-Min Son, before the Saints produced a spirited response, with Charlie Austin bagging a late consolation.
'I can guarantee you that when you see us playing in the summer it will be different than when you see the team now, ' he said. Only two teams have allowed more goals than Cardiff, who have conceded 30 goals. I don't like it so much. "But I feel it was job done and I'm happy with the three points".
"I thought we should have won more comfortably with the chances that we had but all credit to the players", he told Sky Sports.
The new Saints boss is determined to improve the squad through hard work, rather than just wait for the January transfer window to open.
Cardiff, in contrast to their relegation rivals, are now up to 14th courtesy of four wins in their past five home fixtures. Tactically he was very aware, he set his teams out well, but I think being sacked by Man City knocked his confidence as he hasn't progressed since then, whereas when he came to City, people spoke about him being the next top manager. "It was a fantastic decision and I've got to say a big thank you".
Southampton, who parted ways with long-serving head of football development Les Reed earlier in the season, are third from bottom of the Premier League ahead of a tough match away to Tottenham Hotspur on Wednesday.
Southampton (P13, W0, D7, L6) are now on their longest winless run in all competitions since October 1998 (also 13 matches).
Kane has been directly involved in nine goals in his last seven Premier League games against Southampton, scoring seven times and laying on a further two assists.
Saints chairman Ralph Krueger said as the club announced the appointment of the former RB Leipzig boss that he felt the Austrian was the right fit to bring the club forward.