the phrasal verb you are looking for in this context is 'stand up for'
compare 'stand for':
Our organization stands for all that is decent in America. =support (a cause or principle)
Your behaviour has become intolerable. I won't stand for it anymore. = refuse to endure or tolerate
Thanks for your reply! Were there no other mistakes on my post? This sentence was right " Alen should have won the title"? The even has taken place and Mac is giving his opinion after that, so the tense is in the past.
Could you please remove my doubts when using the phrasal verb mentioned below; and tell me if I have made any mistakes in my post?
(We usually use 'doubts' in the plural, as in 'my doubts about going to work for him' even if there is only one thing that you are unsure about.)
Alan should have won the title. The decision was unfair. Mac should/intends to stand up for Alan. ( Here, i want to say that Mac should speak up on behalf of Alan because Alan deserved the title/deserved to win.)
That fixes the grammar, but the context does not really fit the use of 'stand up for'. In a contest, if you do not win, you can protest the decision.
'stand up for' means that Mac supports and speaks up in Alan's defence if he is unfairly criticized or maligned.
Similarly, one can 'stand up for oneself' in the same situation, which means both 'speak up in your own defence' but also implies, 'and have the courage (the 'guts') to do so; assert yourself (because it's easy for other people to fight your battles for you.)