Lady Gaga took to Twitter earlier in August in what was perceived as a controversial marketing move to lure fans into buying more downloads of her new single, Applause.

However, it seems like Katy Perry, Gaga's current arch enemy on the charts, might steal her thunder. According to industry predictions, Perry's new single Roar is set to trump Applause.

Roar sales are already shooting through the roof, as industry sources now suggest that Roar could debut with 525,000 to 550,000 downloads sold by the end of the tracking week on Sunday, Aug. 18. This is a considerable rise from earlier forecasts in which three days ago it was set at 450,000 and six days ago at 400,000.

Both songs officially released on Aug. 12. Perry's single claimed the No. 1 spot on the iTunes USA chart and has stuck it out so far. However, Applause dropped from its initial number 2 spot to number 4 on Friday, Aug. 16.

In an attempt to boost up the sales for her single, Gaga had launched a contest on Twitter this week. The contest offers the opportunity for fans to meet Gaga at one of her shows by becoming one of two fans with the most number of copies of Applause.

Some disgruntled fans didn't look at this as an opportunity to meet the pop icon but more as an unreasonable tactic on her part, and argued that they couldn't afford to shell out money to purchase the same single repeatedly. Gaga responded by suggesting that multiple purchases wasn't the only way to go about this and fans' creativity would count.

Fans are also looking forward to the ultimate showdown between the pop divas as they share the stage at the 2013 Video Music Awards on Aug. 25.

The video for Applause releases on Monday, Aug. 19. This is Gaga's first video in two years and will premiere on VEVO and GMA, the video will also play on the jumbo screens at Times Square.

In other Gaga news, the star lashed out at Perez Hilton for stalking her on Twitter, asking him to back off. She tweeted Hilton directly, who had reportedly spotting her in her apartment complex earlier in the day:

"STAY AWAY FROM ME + MY FAMILY YOU ARE SICK TRYING TO RENT AN APARTMENT IN MY BUILDING TO STALK ME. LEAVE ME ALONE!!!"

In a related tweet, she voiced her disconcertion with Hilton and the paparazzi, posting, "DO I NEED TO BE SHOT IT IN THE HEAD FOR PEOPLE TO UNDERSTAND THAT HIM AND EVERYONE ELSE THAT HARASSES ME HAS GONE TOO FAR? IM A HUMAN BEING."