Anastasija Sevastova stands between world number five Simona Halep and a second title in three years on home soil at the Bucharest Open.
Halep came from a set down on Saturday to beat Vania King 6-7 (3-7) 6-4 6-3 and reach her second final of 2016.
Both players struggled badly on serve early on, the first set featuring a whopping 10 breaks.
However, Romania's Halep, who won the Madrid Open in May and is flourishing once more on clay, raised her level thereafter to avoid an upset.
Sevastova will also be playing in a final for the second time this year, having lost on grass to Caroline Garcia in the ultimate match of last month's Mallorca Open.
On Saturday, Sevastova proved far too strong for Laura Siegemund, the Latvian triumphing 6-3 6-2 against a player 23 places above her in the WTA rankings.