The three big factors in the seo is: 1) Title 2) Content 3) Back links if your site has rich contents as well as few good back links definitely your site will come the top SERP.
there are so many factors are there for getting page rank for any website. Content and Back Links is one of the major factor for get good results. so both are very important factors
I think that maybe your on-page optimization is better than your competitor's Backlinks are important but you are the proof that they are not the only factor for a good ranking.
I've only been doing this for 9 years, but IMO it all depends on how competitive your niche is. The more competitive, the more you need links. And it can all change depending on the algorythm. Trying to rank for a competitive term, all your time and money will be wasted unless you get (over the hump). And it's a big hump.
Well my point is not so much that I gain the number 1 spot for the unique term as much as it is to demonstrate how fast it can be done. It only took me 4 hours to climb to number 1 spot out of 500,000 results. The more broad keywords, as we all know are harder to achieve. However, I can still get those spots too with a little more time. btw, that one article about the yellow pages, brought me in 212 unique new visits yesterday with over 30 different combinations of keywords related to that single article.