The A350 will "compete" with the 787 the same way the A330 "competes" with the 777. It will be a similar size with similar performance characteristics, but it will be less comfortable for passengers.
I would put "compare" in quotes if you want to express that point. They are actually competing for the same moolah, so no quotes necessary in the above.
The camera adds a thousand barrels. - Steven Colbert