Becoming the top boxer in the world is a full-time job that requires more mental toughness than skill. As someone still in the early stages of business, I've learned that mental toughness and fortitude is a vital skill.

Often times, the toughest battle with growing a business is not listening to the little voice inside that's whispering to wave the white flag.

This weekend, mental toughness was on full-display as overlooked underdog Andy Ruiz Jr. took on the undefeated heavyweight champion of the world, Anthony Joshua. Ruiz Jr. was the last minute replacement for this bout.

To the shock of nearly everyone, Joshua suffered his first career loss against Ruiz Jr. after the fight was stopped in the seventh round. Ruiz Jr's. upset this weekend, where he claimed three world title belts, is being compared to when Mike Tyson was upset by Buster Douglas in 1990.

Just thinking of this as a feel-good sports story is missing so much more, Ruiz Jr's. upset provides three valuable lessons in mental toughness for entrepreneurs.

1. How you respond when you get knocked down matters most.

This fight wasn't a cakewalk for Ruiz Jr. as he faced some early adversity when he was knocked down in the third round. While Ruiz Jr. got back onto his feet and composed himself, many thought this fight wasn't going to happen much longer.

However, in this same round, Ruiz Jr. hit Joshua with a counter that changed the entire trajectory of the match.

It's not a matter of if, but a matter of when adversity will strike. When adversity and obstacles present themselves, that's when true character is put on display. One of the first business moments that had me hit the mat was losing unexpected income sources early on when I didn't have a secure business foundation.

For me, my counter that changed my trajectory was finally having to ask for help and remove my giant ego from the scenario. Doing this provided me with opportunities for sustainable growth and more importantly, started to teach me how to actually treat a business as an owner instead of a hobbyist.

If you haven't faced adversity yet, there's a jab on its way. The question is, will you get up off the mat and have a counter ready?

2. Good strategy and execution don't discriminate.

While many focus on talent and other external metrics, those are only one piece of the puzzle. Ruiz Jr. was overlooked by many pundits which were out of his control. However, what was in his control was focusing on strategy and execution.

While not a boxer myself, I have heard of boxers mentioning that smaller boxers are able to adjust easier to the bigger boxers compared to vice versa. Ruiz Jr. not only faced a guy recently in similar stature to Joshua but he also studied Mike Tyson's technique to help.

What's this have to do with your business? Many things.

In the beginning, you may not have the talent nor the resources like your competitors. However, you can make up for this by crafting a detailed strategy and then ruthlessly executing on it.

As I learned in sports, the most talented players often over-rely on talent. And in business, I learned that the companies with the biggest budgets over-rely on their resources. Both instances provide an opportunity for you to win by strategy and execution on the small fundamentals overlooked

Companies with resources forget personalization and treat everyone as a cog in the wheel. Use this to your advantage early on by directly introducing yourself to each follower and connection along with thanking each customer.

3. Looks can be deceiving.

Another reason this fight was a shock to many was the disparity of physiques. Joshua is chiseled and looks like a walking anatomy chart while Ruiz Jr. is the opposite of that.

While Ruiz Jr. isn't going to win a modeling contest, he had something more important than looks: fast hands, fluidity, and mental toughness.

As a mentor reminded me, "Looks can be deceiving. Many people are focusing on looking rich and successful instead of actually being those things."

While it may be tempting to project a certain image to impress social media and other external entities--don't forget your main objective: building an actual successful business.

Shift your focus away from vanity metrics and develop a laser focus on actionable and sustainable metrics. 

There are a lot of talented boxers and entrepreneurs who look the part, but that's not the most important factor. Mindset and preparation trump those who solely rely on talent.