Most people believe that without luck, you can't even have an opportunity and that makes the difference...!

You will not know when luck comes. You will know when opportunity comes. You can encash opportunity and make a rise in your life. Whereas luck happens itself. Opportunities encashed is ever lasting, whereas luck is temporary. A man with a positive outlook will always look up for opportunities and not for luck.

One can cash the opportunity but not the luck

Opportunity comes by luck

Luck bathe bathe mil jata hai opportunity mehnat kerni pardhti hai.

U can grab the opportunity but u cant grab the luck

Luck and opportunity is distinctly different. In fact, luck acts as a catalyst and a precursor for right opportunity. Opportunity is an advantageous chance or a chance, especially one that offers some kind of advantage. Opporunity also mean Favourable conditions or a combination favourable circumstances or situation.
But Luck means A good Fortune or a success that seems to happen by chance. Events determined by chance. Luck can mean both fortunate and unfortunate events like something fortunate or unfortunate that happens to somebody, or a series of such events.
Opportunity can be perceived pre event. The luck is mostly realized post event.

"It's a funny thing, the more I practice the luckier I get." Arnold Palmer

"I say luck is when an opportunity comes along and you're prepared for it." Denzel Washington

"Luck to me is something else.
Hard work - and realizing what is opportunity and what isn't." Lucille Ball

"The truth is, some people do do not see the effort lucky people put in. Like everything else in this life, you must put in effort." Catherine Pulsifer, from Luck, Do You Have It

"Luck is what happens when preparation meets opportunity." Seneca ...more

Source: google search

Luck is nothing other than God's Blessing that enables one to recognise and use an opportunity properly.