Guardiola, who has guided Barca to a League and Cup double, the Champions League, the Spanish Super Cup and now the UEFA Super Cup since taking over last year, said the 22-year-old kept his cool on a hot and humid night to seal their victory.
"He took his chance very well and, of course, I am delighted for him - and with him," said Guardiola. "But I don't make players, I can only encourage them and help them but he scored an excellent goal and it gave us victory in a very tough match."
Pedro has developed though Barca's youth ranks and played a part in their Champions League triumph over Manchester United in last season's final when he was a late substitute in Rome.
He made 14 appearances for the club last season and is hoping to play more matches this term as well as progress from the Spanish Uunder-21 side to the senior national team.
Pedro made his mark on Friday by coming on in the 81st minute for Zlatan Ibrahimovic and rifling in the winner from the edge of the area five minutes from the end of extra time.
"Like Bojan (Krkic) he has the chance to do well for us and he is part of a very good squad here," said Guardiola.
DIFFICULT CONDITIONS
He added that Barcelona were far from their usual smooth-running selves and battled to overcome a tough Shakhtar side as well as a bumpy pitch and difficult conditions.
"We were two seconds too slow tonight, but it is August. People are partying, there are boats in the harbour, people are on holiday. It's not like in April or May when you are firing on all cylinders, but we will get there.
"We have already won two trophies this week and the league season has not begun yet. But we will improve, there is a long way to go," he added.
Guardiola also defended the performance of expensive new signing Ibrahimovic from Inter Milan, who had a fitful game.
"He has not trained with us fully, he has been injured, but he will be absolutely fine," he said. "He is going to be here for years, not just 10 days. He can play in any system we use, he is a great player and I have no worries about him at all."
Shakhtar coach Mircea Lucescu, who won the Super Cup with Galatasaray in 2000, said his side should have been awarded a penalty, claiming Ilsinho was bundled over in the penalty area just before the end of extra time.
"I feel a bit bitter as we played a good match and should have had a penalty right at the end. No doubt about it, 100 percent," he said.
