Berdych was tested late in Friday's 6-3 6-4 1-6 6-4 win over Australian youngster Nick Kyrgios on Rod Laver Arena.
The two-time Australian Open semi-finalist was cruising until he dropped the third set, but he regained his composure to reach the last 16 for a sixth consecutive occasion at Melbourne Park.
Despite the third-set collapse, Berdych told reporters he is looking ahead to the second week and a showdown with Roberto Bautista Agut in a positive frame of mind in his bid for a maiden grand slam.
"I probably stepped down a little bit from the gas and I just probably gave him more space on the court," Berdych said when asked about the third set.
"Kyrgios a great player. He just took advantage of that. It was just couple of points which on one side it was just close in, the other one was close out. All of a sudden the gap just become huge as a score.
"But I didn't feel that way, that it's going so fast. He can play big. But I just refocus myself and then play well again in the fourth set."
Berdych added: "I think the week's been quite solid. So far it's been guys that I never play before. That's becoming more and more of those, so that's good. That's what I'm pleased with.
"Especially my game, it's getting better and better while the matches are keep coming. So that's also a very positive for me.
"I think for the third round, it was a very, very tough and difficult opponent. So it was a very good test for the third round.
"So feeling good. Body's fine. So looking forward to play more."