The Spanish champions won their fifth trophy this year after claiming a 1-0 victory over Ukraine's Shakhtar in Monaco.
They needed an extra-time goal from Pedro Rodriguez to settle the game in their favor.
"It was a terribly tough game," Guardiola was quoted as saying by Barcelona's official website.
"In other finals we were more into the match rhythm and in the middle of competition, but tonight caught us on the back of our holidays.
"The state of the pitch was also an embarrassment. They (European governing body UEFA) talk about looking after the players, saying they should put on a show … and then they make us play on pitches like this."
Winger Pedro, who also scored in Barca's 5-1 aggregate win over Athletic Bilbao in the Spanish Super Cup, once again impressed.
The 22-year-old scored the winner five minutes from the end of extra-time after a neat exchange of passes with Argentine forward Lionel Messi.
"I congratulate the people that discovered him and helped him grow. I am reaping the benefits," Guardiola commented.
نرشح لكم
تقرير ألماني يكشف سبب استبدال موسيالا أمام لايبزج
حمزة عبد الكريم ضمن قائمة برشلونة لمواجهة بازل
"لاعب يعشق المراوغة".. باريس سان جيرمان يضم ميكا جودتس
الإنجليزي الخامس تاريخيا.. إنتر يضم سبينس من توتنام
ماذا قال مدرب طرابزون بعد أول تعادل في وجود محمد صلاح
بمشاركة هيثم حسن.. سلتيك يفوز برباعية ويتأهل لنصف نهائي كأس الدوري
في ظهور محمد صلاح الأول.. طرابزون يفتتح الدوري التركي بتعادل مع قاسم باشا
فوز أموريم الأول أمام فريقه السابق.. ميلان يتفوق على مانشستر يونايتد برباعية وديا











