Some days you do whatever you ‘‘kneed’’ to catch a big fish.

Jimmy Martinez knows that after catching and releasing a 73.2-pound blue catfish Sunday at LaSalle Lake. Biologist David Wyffels agreed that it was the biggest he knew of from the cooling lake south of Seneca.

‘‘We were on bikes and were about to move, but there was a boat in the way, and that is right when it hit,’’ said Martinez, who was fishing the lake for the first time. ‘‘When it took off, I set the hook. He tugged back like another person.’’

The pull-back was hard enough that Martinez, a 37-year-old construction laborer from Elgin, slipped and slammed his knee on the shoreline rocks.

‘‘I set my drag, and he was gone,’’ Martinez said. ‘‘He was taking all my line, but I got up and started fighting him. He did not want to come up. He would go side to side with force.

‘‘When I saw the fin, I couldn’t even feel the pain. [Now] my knee is all swelled up and purple.’’

Martinez and cousin Erik Martinez, noted for his Fish of the Week for a 52-pound flathead catfish caught from Fox River in 2016, were using about seven worms on a hook.

It was about 1 p.m. Sunday when Martinez landed his fish after a 15-minute battle.

‘‘I had just bought new gear, and it was the first time using it,’’ Martinez said.

He had an Abu Garcia 7000 series reel with 50-pound PowerPro line on a Big Cat Fever medium-heavy rod.

‘‘We were geared up for it,’’ said Martinez, whose previous-biggest fish was a 15-pound flathead from the Fox. ‘‘We were going for big fish.’’

When landed, the blue nearly bottomed out his digital scale at 73.2 pounds.

‘‘We were screaming and high-fiving,’’ Martinez said.

Then he carried the big blue down for release. It is touching to see him brush off some gravel from the blue’s head when he releases it. The video is posted below.

On the day, they caught six other blues of 3 to 8 pounds.

As to his big one, Martinez said: ‘‘He had to be released. That is a trophy fish. It took years to grow that big. We have to keep a trophy fish like that in the lake.’’

Martinez is headed back to LaSalle this weekend.

‘‘Man, I was stunned when I saw him; I couldn’t even believe it,’’ Martinez said. ‘‘I still can’t believe it. I was looking at the picture all day.’’

Stray cast

If Loyola can reach the Sweet 16, one of us should be able to catch a 6-pound, 8-ounce smallmouth bass from the Illinois waters of Lake Michigan, even without a nonagenarian conduit to the Almighty.

Follow me on Twitter @BowmanOutside.