The Spanish top seed, who completed a career Grand Slam by winning the US Open last month, eventually saw off his Serbian opponent 7-6 (7/4), 4-6, 7-6 (9/7). Earlier, French fifth seed Monfils used an array of fine passing shots to beat Radek Stepanek of the Czech Republic 6-3, 6-3, staying in control throughout their semi-final.
"I played well in the first set, I played an unbelievable tie-break. After that, I lost my focus and lost my concentration in one game on my serve and it was impossible to come back in the second set," said Nadal.
"After 5-3 in the third, I started to play very bad. I can't understand why I lost my serve. It's impossible for me to understand how I lost. It was on my serve at 5-all and 30-love. That was the worst moment of the match for me.
"After that, I won and I'm in the final. I'm happy for that, but I'm not happy with the way I played in the last three games of the match," he added. Nadal broke Troicki in the eighth game of the final set to lead 5-3, but let the Serbian come back into the match as he charged hard to the net to break back.
Troicki, ranked 54th in the world, scored another break thanks to a forehand volley by Nadal that landed in the net, taking the lead 6-5, but he also failed to serve out the match, double-faulting on a break point to tie at 6-all.
Troicki was the first to get to match point, leading 6-5 in the tie-breaker with the Spaniard serving, only to see Nadal hit his favourite forehand winner. Troicki was server on his second match point, but hit an easy forehand into the net.
Nadal gathered the momentum to hit a service return winner to take a commanding 8-7 lead and the match was his when Troicki hit his forehand wide to surrender the two-hour-38-minute battle.
"I played a great tournament and I'm still happy that I reached the semi-finals," said Troicki. "I could have lost in the second round to (Austria's Jurgen) Melzer.... I was a match point down. And I made it to the semi-finals. Right now, I'm disappointed, but still I think it was a good result for me.
"It gave me a lot of confidence for the next tournament. I hope I forget this match," he added. Monfils, who lost to Stepanek at the Brisbane International earlier this year, said the key was practice time against a serve-and-volleyer.
"It's tough, because there are not a lot of guys like him, I mean serve and volleyers. I tried to return good, to return with consistency, and tried to make him hit a volley every time, and I had a bit of luck," said Monfils. "In Brisbane, I had a shoulder problem, so I couldn't serve 100 per cent. I came today very strong. That made the difference," he said.
