luck into (something)

to get or find something good by chance.

The flight was pretty empty, and the passenger across from me lucked into three seats to himself.

• on a par with
• on a par with someone
• on a par with something
• on a roll
• on a shoestring
• on a silver platter
• on a slippery slope
• on a tangent
• on automatic pilot
• on a wing and a prayer
• on back
• on balance
• on behalf of
• on behalf of someone
• on bended knee
• on bended knees
• on best behavior
• on blocks
• on board
• on borrowed time
• on call
• on case
• once again
• once and for all
• Once bitten, twice shy.