Sevilla performed admirably despite their 3-2 defeat and probably deserved to at least take the match to penalties.
However, Real Madrid scored two last-gasp goals to down the Andalusian side. Firstly, Sergio Ramos equalised to level the match at 2-2 in the third minute of injury-time, then Dani Carvajal scored a wonderful winning goal in the penultimate minute of extra-time.
Sampaoli believes that his side did not make the most of the moments when his side where on top.
"We lacked the ability to consolidate the large dominance of the second half, to transform any chances we had into more and be more forceful," he said speaking after the match.
"When you're not able to score, the opponent with the players it has can damage you, and they made the most of their virtues".
Despite this, he did concede that he was "proud" of his players' efforts.
"I am proud of the game, in the short time working together we showed bravery, and the way we played against the European champions was exciting for me, I appreciate it a lot".
Sevilla have now lost the Super Cup three times in a row after losing to Madrid (2014, 2016) and Barcelona (2015).