EASTBOURNE, Great Britain - Former World No.1 Angelique Kerber rallied from the brink of defeat to knock out Russian rival Daria Kasatkina, 6-1, 6-7(3), 7-6(3) and reach the final four at the Nature Valley International.

"I think it was a tough battle for both of us," she said during her on-court interview. "We played very well, especially in the third set. It was just a fight, and I'm happy I won in the end, but it was really close and such a good match.

The two-time Grand Slam champion and 2016 Wimbledon runner-up had lost three of her last four matches to Kasatkina, who reached her first major quarterfinal this spring at Roland Garros, but turned the tide even as the 21-year-old forced a final set tie-break, striking a screaming forehand winner to clinch victory after two hours and seven minutes on Court 1.

In their first grass court meeting, Kerber used her clear comfort on the surface to blitz Kasatkina in the opening set, hitting seven winners to the Russian's nine unforced errors.

Both setttled into the second set as Kasatkina aimed to level the match, twice breaking the German ahead of the ensuing tie-break. From 2-3 down, the youngster raced through the final five points of the sudden death to force a deciding set - just the second in their six-match rivalry.

"I think I started really well in the first set, and she came back in the second. The third one was more up and down. I was just trying to fight until the last point; that was the only thing on my mind."

Kerber grappled with frustrations as she fell within five points of defeat as Kasatkina served for a 5-2 lead, roaring back to twice serve for the match at 5-4 and 6-5.

Kasatkina duly broke each time and edged ahead 3-1 in the final set tie-break only to see a reversal of the second set as Kerber won six points in a row to end the quarterfinal classic.

In all, the No.4 seed struck an impressive 41 winners to 32 unforced errors, while Kasatkina was in striking distance with 31 winners but was ultimately undone by 38 errors and 10 double faults.

Standing between Kerber and her second final of 2018 is top seed and fellow former World No.1 Caroline Wozniacki, who eased past No.8 seed Ashleigh Barty in straight sets earlier in the day.

"I think it'll be another good match. I know Caroline very well; we've played so many matches in the past, so I'm looking forward to playing her again."

Kerber leads Wozniacki 8-6 in their head-to-head, and beat Wozniacki back in 2016 to first ascend to the No.1 ranking at the US Open, but the reigning Australian Open champ won their only meeting this season in three sets at the Qatar Total Open.

More to come...