Sarcasm/irony is all about the voice. If you say it sarcastically, then anything can be sarcastic.
言い方が大切です。
"彼は今までで一番偉大な大統領だよ、下から数えてね"
ー>The #1 president, if you count from the bottom.
うわ~すごい大統領だね。
Wow what a great president.
ー>これはトーン(言い方?声?)が大切です。
The way you say it is very important.