Del Potro looked in top form ahead of the Australian Open with his second straight-sets victory, having beaten Canadian teenage star Denis Shapovalov 6-2, 6-4 in the second round.
The Argentine world number 12 now goes into a final against 2016 Auckland champion Bautista Agut, who came from behind in an epic a battle against Dutchman Robin Haase featuring three tie-breaks.
The Spanish player swept through the first set in only 31 minutes as del Potro seemed to struggle in warm conditions on a packed center court.
However, Del Potro broke at the ideal time - in the 10th game - in the second set to level the match.
This Is Toyota's 1000-Horsepower LMP1-Inspired Hypercar Concept
However, Toyota says it does give us a taste of what the company aims to achieve with its next-generation sports cars. The hybrid Toyota GR Super Sports Concept is based on the Toyota WEC Championship competitor, the TS050 Hybrid.
"I didn't play another match during the day, so I felt a big difference in the weather, but it's not an excuse - I had my chances to win, too".
The advantage in the third set went one way then the other until Bautista Agut broke del Potro to lead 6-5, then saved a break point to win the match in 2 hours, 7 minutes.
"Juan Martin is very tough to beat and I think I just played two fantastic games at the end of the match". Every weapon in their armoury was on display, with Haase even switching his racquet from the right toleft hand to reach shots swinging away down the backhand side.Del Potro and Ferrer's rallies were generally shorter as they slugged it out from the base line. "I tried to have Juan Martin moving around the court".
"David is a great fighter, we have a great relationship and it's going to be an interesting match to watch". I think the crowd enjoyed the game. "The end was unbelievable when I saw the ball in I went insane, I was so happy".