Karolina Pliskova became the World No. 1 on Monday, just two days ago. She supplanted Angelique Kerber after the German actually enjoyed a modest run at the top of the world tennis rankings. Kerber's total stay lasted 34 weeks, however, there's good reason to believe that Pliskova's current stay at the top of the WTA Tour will not come anywhere close to that.

Several players within striking distance

Pliskova could get hunted down for the World No. 1 ranking by any of several players. Kerber is among those players, however the German is actually approaching a time of her season where she has points to defend.

Despite falling in the rankings lately Kerber could actually fall some more in the near future. She won the US Open last season, but doesn't appear poised to do it again later this season.

Simona Halep, Garbine Muguruza, Elina Svitolina, Caroline Wozniacki, Johanna Konta, and Venus Williams are all within striking range of Pliskova. That doesn't mean that one tournament will change everything, but if any one of those players was to enjoy a strong run, she might end up top ranked. A big reason for that is that Pliskova backed into the No. 1 position, instead of charging in.

What does it mean to 'back-in' to the top?

When you 'back-in' to the top ranking, you get top spot due to another player playing poorly over the short run.

Pliskova herself didn't do well at Wimbledon 2017, but she still got to No. 1 because of Kerber's failure at the event. It's that failure that saw Pliskova back-in to the World No. 1 position. Charging in is more like what Kerber did as she took top spot last year with her win at Flushing Meadows directly.

When you back in to the top spot, it means that dated results instead of recent ones are keeping your ranking high.

Pliskova's No. 1 ranking references her entire season, but her summer of 2016, results from almost a year ago, are ones that are currently playing a big role in buoying her. The problem is that those results from the summer of 2016 are about to drop off. The Czech player has a title to defend in Cincinnati and she has a runner-up finish to defend at Flushing Meadows.

If she does poorly, she stands to lose a lot of ranking points.

That opens the door, mainly for Halep or Muguruza to take over the top spot. On that matter, the Spaniard has to be judged the more talented player for sure. However, Caroline Wozniacki has peaked at the US Open twice before, with two runner-up finishes in the past. Konta's hard court abilities can't be discounted and neither can Williams'.

While Pliskova can't be ignored either, she may ultimately need a title to stay ranked No. 1 following the US Open. So far, her results in majors this season haven't been top notch. Her run to the French Open semifinals is the highlight, with disappointing results in Melbourne and at the All England Club.

Muguruza and Halep are the bright lights right now, especially the latter, as she did not do a lot with her North American hard court schedule in 2016. That means that she could gain a lot in the weeks ahead, so much so that she could be No. 1 before the end of the summer.