Carreño Busta played four qualifiers in his first four matches at this year's event, making him the first player in the Open Era to face that many qualifiers in a slam.
Kevin Anderson, of South Africa, reacts after beating Pablo Carreno Busta, of Spain, during the semifinals of the US Open. Despite Carreno Busta's toughest fight, it still was not enough to match up against Anderson's explosive game as the 28th seed eventually served out the third set 6-3 after 39 minutes.
Anderson, No.32 in the world, will be the lowest-ranked man to play for the title at Flushing Meadows since the ATP rankings began in 1973 and the first South African since Cliff Drysdale in 52 years.
The victor of the match would meet either 15-time Grand Slam victor Rafael Nadal of Spain or 2009 US Open champion Juan Martin del Potro of Argentina in Sunday's final. It was the first time when Anderson's game was stretched to four sets but the Italian failed to stop Anderson's stunning run at the US Open, losing by 6-4, 6-3, 6-7, 4-6. Anderson made the most of his opportunity, nailing a backhand victor to take the set 7-5 and level the match.
The South African had the flawless start to the third set especially when he strolled to a comfortable service hold before earning a 0-40 lead on the return.
Kevin Anderson has taken control of his U.S. Open semifinal against Pablo Carreno Busta, winning the last two sets. Instead, the South African hung tough and emerged a 7-6 6-7 6-3 7-6 victor to make his maiden Slam semifinal. I think just my emotion at the end summed it up.
"I thought the beginning of the match, I felt a little bit nervous", Anderson said.
I am proud of Kevin for sticking it out and surviving in one of the toughest global sports.
"I really don't know what to say right now", Anderson said in his ESPN on-court interview.
Anderson, who stands at 2.04 metres tall, climbed into his player's box to embrace his wife, brother and coach Neville Godwin after Carreno Busta's forehand found the net to finish their almost three-hour contest.
"He's obviously very confident", Anderson said.
Carreno Busta surrendered a 40-0 advantage in his next service game, which went to deuce five times before he eventually held to force Anderson to serve for the match.
Anderson, born in Johannesburg in May 1986, had never gone beyond the fourth round in more than a dozen appearances at Grand Slam events. "I've put in a lot of work, so it feels good to reach a milestone I haven't before". I had to change a couple of things after the first set because I was playing on his backhand too much and he was waiting for me there. You know, his serve, he's been serving very well, it looks like.
Kevin Anderson is living the dream right now.