Nadal won Monte Carlo last weekend while Nishikori lost the Miami final to Novak Djokovic, the last event he played prior to Spain.
He will need to beat defending champion Nishikori after he beat Benoit Paire 6-3 6-2.
The two players to have dominated the Barcelona Open in recent years, Rafael Nadal and Kei Nishikori, will meet in the final of this year’s tournament after securing straight-sets semi-final triumphs.
Nishikori appeared to have a grip on the second set right at the outset, as another Paire double-fault contributed towards conceding a 2-0 lead, but the Frenchman got a break back instantly to give himself hope.
Rafael Nadal admitted he is controlling the nerves that clouded his 2015 season better after seeing off a second set fightback from Fabio Fognini to reach the Barcelona Open semi-finals with a 6-2, 7-6 (7/1) win on Friday.
Nishikori hasn’t consistently looked great in Barcelona, but he has found alternative ways to win when one particular aspect of his game wasn’t working.
Some determined defence and retrieval by Nadal in the seventh game forced Kohlschreiber to greater effort, kept him pinned way behind the baseline, and drew errors on his serve.
A relatively easy first set for Nadal was followed by a second-set revial from Fognini, who came close to pushing the match to a deciding set.
The second set was similarly straightforward, with Nadal stepping into the court and firing big forehands to keep his opponent pinned firmly behind the baseline. “I’m happy about the victory and very happy about the way I played today”, Nadal told Alex Corredja on court.
Nadal saw off Philipp Kohlschreiber 6-3, 6-3 on Saturday to return to his first final here since 2013, when he won the tournament a record eighth time. Paire stunned Nishikori at the US Open past year.
Nishikori extended his winning streak in Barcelona to 12 matches with a 6-3 7-5 success over Chardy.
To his credit, Fognini snaffled all three of them, but with Nadal earning a whopping 16 break points of his own and converting five of them, the Italian could never really gain the ascendancy.