DUBAI, UAE - Russian Daria Kasatkina held her nerve when it mattered the most in the first round of the Dubai Duty Free Tennis Championships on Monday to take out 2012 champion Agnieszka Radwanska in straight sets, 7-5, 6-4. 

Despite leading by a break - or two, as was the case in the second set - the Russian was forced to come up with her best tennis in the late stages of each set to secure victory.

"She's a big fighter and she's playing incredible, so it was a really tought match, as always," Kasatkina said on-court after the match. "I didn't think about [the lead]. As I said, Aga is a big fighter, so I had to be ready for everything.

"Everybody knows that Aga, she's a tricky player. She can play an unbelievable winner from any part of the court, doesn't matter where, so I was kind of ready for that. I was just trying to focus only on my shots. If she hits some unbelievable shot, not to put too much attention on this."

Lasting just under two hours at one hour, 56 minutes, there was little to separate the two players over the course of the match. Though each struck 21 winners, it was Kasatkina's effectiveness on break points which allowed her to edge a second career victory over the former Wimbledon finalist.

The Russian converted on seven of 13 opportunities she was given in the match, while Radwanska was successful on just five of 11 attempts. 

After moving ahead an early in both sets, Kasatkina was forced to dig deep late, as she needed five set points to finally steer herself to a one-set lead.

The Russian led 40-0 on her seve at 6-5, as she looked to put an end to a string of four straight breaks, but double faulted twice and struck a first-ball forehand unforced error to see 

In the second set, she saw a double-break lead slip at 3-0 as Radwanska drew level, but she pushed through to win three of the last four games from that point to move safely through to the second round.

"Against these kind of players, you have to be patient, otherwise you can go crazy," Kasatkina said.

"You can lose few important points in a row. This is what they're waiting for. The important part was really mental."

Kasatkina will next face the winner of the match between No.7 seed Johanna Konta and Anastasia Pavlyuchenkova. 

"I think she can do everything on court. She has very good hands, very good touch. She can mix it up. I think that what makes her very difficult opponent," Radwanska said in defeat. "I think in the second set, and also in the first set, I had a bunch of opportunities. Maybe [I made] bad decision in those particular moments [on] a couple of break points that I didn't use.

"In those kind of tight matches when you're not using those chances, they're really going to turn around everything."