You use if only with past tenses to introduce what you think is a fairly good reason for doing something, although you realize it may not be a very good one.
She writes me often, if only to scold me because I haven't written to her.
They deserved their title, if only for winning in Dublin against their main challengers.
See full dictionary entry for if
if only in British English
an expression used to introduce a wish, esp one felt to be unrealizable
See full dictionary entry for only
if only in American English
would that; I wish that
if only they would leave; if they would only try harder
See full dictionary entry for only
Examples of 'if only' in a sentence
if only
And if only one letter will be issued in future, what information will it be based on?
Times, Sunday Times (2016)
If only one is to play, it should be Duckett.
Times, Sunday Times (2016)
If only we could just get on and read it and forget about all the other stuff.
Times, Sunday Times (2012)
If only it could get in the air.
Times, Sunday Times (2013)
It looks as if only two things are certain.
Times, Sunday Times (2013)
We also decided that if only one of us was picked then neither of us would go.
Times, Sunday Times (2012)
If only this were just a business story.
Times, Sunday Times (2011)
Imagine the effects on social life that might occur if only one individual were needed.
Harris, Marvin Cultural Anthropology (1995)
If only they would just leave it alone.
Admiral Sandy Woodward, With Patrick Robinson ONE HUNDRED DAYS (2003)
If only he could get better and we could all be happy again.
Times, Sunday Times (2012)
Imagine if only one in ten people finished a book or a film?
The Sun (2013)
If only it were just in cinemas!
Times, Sunday Times (2007)
If only he can get used to the idea of putting ketchup on his tables.
Times, Sunday Times (2007)
If only the good vibes lasted.
Times, Sunday Times (2006)
Certainly relationships will change, if only in subtle ways.
Pearson, Althea Growing Through Loss and Grief (1994)
That is good news, if only because consumers are spending more.
Times, Sunday Times (2006)
You can't win it if only one or two are chipping in.
The Sun (2015)
Now a deal looks distinctly possible, if only after some hard negotiations over the next two years.
Times, Sunday Times (2007)
It smells so good; if only they could get it to taste as good as it smells.
Times, Sunday Times (2011)
I no longer drive her anywhere if only the two of us will be in the car.
Christianity Today (2000)
If only for health reasons.
The Sun (2014)
It is, if only for this reason alone, absolutely fantastic to watch.
Times, Sunday Times (2006)
There's always another way, if only we can calm down enough to think things through.
Times, Sunday Times (2010)
Good grief, if only.
The Sun (2007)
Still, he deserved the chance to say his piece, if only because he may not enjoy the platform for much longer.