The final episode of Smith's first series as the Doctor attracted just 5.1 million viewers, while bookies recently slashed odds that the actor would be dropped from the role.
However, fan Peter Bell told WalesOnline: “I was reserving my judgement on Matt Smith until I saw him in action and I must admit I was a little sceptical because I thought he was too young to play the Doctor.
“Now I’m happy to admit I was wrong. He was good at first and he just got better and better as the series progressed - better even I think than [David] Tennant.”
Bell argued that Smith's performance was not to blame for the lower ratings.
“We had great weather on Saturday and most people don’t want to spend summer sat indoors watching the TV.” he said.
Matt Hills, a doctor at Cardiff University who has written several books on the series, also suggested that the viewing figures could be misleading.
“These ratings figures need to be viewed in the context of a developing shift towards on-demand viewing." he explained. “Audiences know they can catch up with Doctor Who via services such as iPlayer, as well as through BBC Three repeats.”
Doctor Who showrunner Steven Moffat also recently suggested that the show's overnight figures were being affected by on-demand viewing.