Reina was impressive for their draw with Reading last weekend.
"I'm happy because we've already kept more clean sheets than last season but there's still plenty of room to improve it," said Reina, who has twice been hampered by injury this season.
"As I said a few months back, there have been a few ups and downs.
"The start of the season was a bit rough to me: since November/December I have probably turned the corner and picked the form up again.
"Hopefully it will stay for long. As I always do, I do my best and work hard on a daily basis.
"I looked after myself a little bit better in the last few months and tried to be as fit as possible."