Djokovic found his form in impressive fashion as he moved into the final in Miami without dropping a set, but he came up short against big-serving Mensik in two tight tie-breakers.
The Serbian legend should dust himself down and take confidence from his run in Miami, with Roddick suggesting he has proved he can still win a record-breaking 25th Grand Slam title, even though he is set to celebrate his 38th birthday next month.
"He can still win a major, especially when the surface is giving him some love, like it was in Miami. Where the ball is getting through the court, where he doesn't have to protect the sidelines as much and doesn't have to play as much defence," Roddick said on his latest Served podcast.
"Extraordinary. There's just not a world that anyone is saying Djokovic was disappointing because he didn't win that final. What? He's almost 38 years, didn't drop a set until the final and lost two breakers. If they played the match again tomorrow, I would bet on Novak on that surface.
"What Novak is doing is just crazy. I didn't think we would see this much of him this year. He stayed in the States for a month to play Indian Wells and Miami."
Roddick went on to suggest the arrival of former rival Andy Murray in his camp as a coach has given him a fresh incentive to shine, as he backed the most successful player of all time to challenge for the title at the French Open.
"Is the product he is putting out there good enough to win a major? Yes, it is. Will it happen? I don't know," continued Roddick,
"You talked about Roland Garros, three out of five [sets]. This guy did win the Olympics there a few months ago.
"He seems happy playing right now. He seems motivated to play right now. He has someone different to report to. Maybe that's the benefit of the Murray situation.
"So long as he is in tennis, it's better to watch. Even a version of him, and I say this gently, where he is 'only' the third favourite in every Slam now.
"He's going to be 38, but are you going to put him outside of the top three to win Wimbledon? No, he's your third favourite. Sinner, Alcaraz and Djokovic.
"It's just amazing that he's still going. Connors made the semi-final of the US Open and it was like he rode a hot air balloon to the moon," he added.
"Now guys are kinda doing this. These three have reset the expectations on everything."
Djokovic has entered the Monte Carlo Masters that gets underway next week, as he looks to make a swift transition from hard courts to clay as he counts down to the French Open next month.