Updated: Jun 22
City beat Zinedine Zidane's boys at the Bernabeu in the first leg of their UCL last-16 tie.
The Champions League and 2019-20 Premier League campaign came to a halt due to COVID-19 chaos.
Man City star Mahrez is convinced Guardiola's Citizens can win Europe's elite competition.
Riyad Mahrez believes Manchester City can win the Champions League this season.
Mahrez, who joined Man City in the summer of 2018, has been looking forward to returning to action after football came to a standstill in March due to the coronavirus pandemic.
Pep Guardiola's Citizens thrashed Spanish giants Real Madrid 2-1 at the Santiago Bernabeu in the first leg of their Champions League last-16 match in February, and Algerian winger Mahrez has no doubt his side have the quality needed to win the competition.
"I think it is a good time to win the Champions League," Mahrez said. "We have the team, we have the manager, we have everything, so it is a good time. I don't know if we are the best, but we are good enough to win it.
"The Champions League is difficult, everyone wants to win it, so it is going to be a big battle."
On going two months without football due to the COVID-19 shutdown, Mahrez said: "It was a bit long without football, but we adapted and now we are back, so it is good. With the pandemic going on [training at home and doing online sessions with the group] is something we had to respect and now we have come back to training it is very good.
"Step by step we are getting fitter, so it is good. I am excited. It was good to see my team-mates and the coaches again. It was good to train with everyone and we have had very good weather as well!"
The former Leicester City star added: "I think we were good [before the break].
"I wouldn't say we were at our peak, but it was good. We are going to train again and come back because it has stopped for everyone, not just us. It is going to take time to come back and be the way we were before, but it is the same for every team."
Second-placed City are 25 points behind Liverpool in the Premier League table with a game in hand, but the Reds need only two wins to be crowned champions.