he found out the morning of the game he was starting after Cahill returned from national team duty with a tendon injury.
"It’s my job, my profession and I have to be ready when I am called upon and show the manager I can contribute and help the club," he told the Chelsea Web site.
With Chelsea out of the EPL race for the top four, its Dutch manager, Guus Hiddink, gave three players their debuts: veteran Brazilian Alexandre Pato, academy product Jake Clarke-Salter and Miazga. Ruben Loftus-Cheek, 20, also started.
"It's good to see Loftus-Cheek, Clarke-Salter and Miazga coming in," said Hiddink. "We cannot win anything, which makes it easier. It's good to see how they deal with the pressure. I always like to bring in youngsters, and now we have the rest of the season to do it more frequently."
Hiddink said it would be hard to judge Miazga off the Villa game.
"To be honest this wasn't the toughest game," Hiddink admitted. "You have to consider also when a real good war is going on how you cope with that, but it's a good first step up for him. He's coming from a league that is a bit naive compared to the Premier League, and he has to get used to a little more freedom given to the attackers by the referees, which I like. He has to cope with a little bit of a shuffle, of a push that in other leagues the referee would give free kicks for. That's the naivety he has to leave as soon as possible but I didn't see much of that [against Aston Villa]."
Miazga said he would make himself ready for more opportunities.
"It was a good debut for me," he added. "I’m happy to contribute to the team and now I have to work hard in training to keep trying to get more chances. This is the highest level. Leading up to professional games you're always a bit nervous and anxious, but once you get onto the pitch it's business."