As I prepare to wave bye-bye to my 50s in a few months, 30-something doesn’t seem old at all. But in the world of professional tennis, it’s nearly ancient, which is what made this year’s Australian Open tennis championships so captivating and memorable.

Tennis geeks like me were mighty stoked a few weeks ago when Serena Williams, 35; Venus Williams, 36; Roger Federer, 35; and Rafael Nadal, 30, each won six matches in the brutal heat of the Australian summer to make it to the finals.

As the old joke goes, I have underwear older than these four. But they have spent decades on the grueling pro tour and endured injuries, surgeries and illnesses along the way, making their climb back to the top truly amazing.

I know what rehab is like — it can be painful, lonely and frustrating. But after my various and assorted injuries and surgeries, I’ve just tried to get back to something similar to a “normal life,” which is a far cry from the fitness required to play pro tennis.

And while we tennis fans saw the Williams sisters, Federer and Nadal holding up trophies and collecting huge paychecks in Australia, we didn’t see them on the many discouraging, ordinary days when they had to muster up incredible self-discipline and emotional fortitude to go to the gym, get out on the courts and dare to hope they could ever again win.

The fire and strength inside of them inspires me. I’ll never win another tennis tournament, that’s for sure, but I still have a race to run. We all do.

The Apostle Paul, writing to Christians of all ages, said, “let us run with endurance the race that is set before us.” (Hebrews 12:1)

Do you think Paul believed in early retirement? Did he believe in spending his last years sipping mojitos by a pool?

No way. Consider what he wrote near the end of his life: “I have fought the good fight, I have finished the course, I have kept the faith.” (2 Timothy 4:7)

Finishing well in professional sports earns a lot of earthly attention and applause, but I’d much rather have God’s approval for ending my earthly “race” well, for staying faithful to Jesus Christ until my last breath.

To do that, I’ll have to get up every day and push through some pain, discouragement and opposition. I’ll have to endure. I’ll have to maintain Paul’s mindset: “I press on toward the goal for the prize of the upward call of God in Christ Jesus.” (Philippians 3:14)

I can do that, as every follower of Jesus Christ can, because we have a source of fire and strength in our hearts that surpasses anything in or of this world: the Holy Spirit of God.

I was recently blessed to hear a talk by Jill Briscoe, a British woman in her 80s who has spent most of her adult life writing and traveling to every corner of this world to teach the truths found in the Bible.

One thing she said that resonated powerfully with me was her admonition to keep “carrying our crosses” — to keep doing what God has called us to do — all the way home. We’re not finished until we breathe our last earthly breath.

In 1 Corinthians 9, Paul encourages us: “Run in such a way that you may win. Everyone who competes in the games exercises self-control in all things. They then do it to receive a perishable wreath, but we an imperishable.”

If we have a pulse, we have a purpose — a purpose so much higher, eternally significant and, ultimately, more rewarding than winning tennis championships. Let’s renew our determination to push through the sometimes brutal heat of this life to make it home.

All the way home.

Mary Ann Crum (maryanncrum.com) lives in Abbeville and is the author of two books, “A Giggle Goes a Long Way” and “Live.Learn.Laugh!” She can be reached at maryanncrum@gmail.com.