The fifth-ranked Zverev kept patient, though, and took his chance when it came as he rallied to beat his unheralded Chilean opponent 1-6 7-6 (7-4) 6-2 on Friday for a spot in the Italian Open final.
"I was just hanging on the second set. I brought my energy up," Zverev said. "He hit me off the court in the first set and I didn't play well at all, but he was a big reason why. He gave me no rhythm."
In Sunday's final, Zverev will face another Chilean, Nicolas Jarry, who beat Tommy Paul 6-3 6-7 (7-3) 6-3 on the American's 27th birthday.
The 24th-ranked Jarry came back from a set down to eliminate Stefanos Tsitsipas in the quarter-finals and will be playing his first Masters Series final.
It was an appealing contrast in styles between the big-serving 2.01m Jarry, who goes for a lot of his shots, and the more defensive-minded Paul, who grinds it out and likes to make his opponents play longer points.
Zverev, the 2017 Rome champion, had the pinkie on his left hand bandaged following a fall in his previous match, after which he said his finger was "crooked." The German plays right-handed but uses a two-handed backhand.
He said his pinkie was swollen and he was using painkillers.
"I tore a capsule. ... But I didn't break any bones," Zverev said. "The finger is still very, very big. It was manageable."
It's Zverev's third final in Rome. He won in 2017 by beating Novak Djokovic in straight sets for his first Masters Series title. He lost to Rafael Nadal in the title match a year later.
"I've been here before," Zverev said. "I know what it takes and hopefully I can use that."
Rome is the last big warm-up before the French Open starts on May 26.
Zverev, who has disputed a penalty order from a German court over allegations that he caused bodily harm to a woman, faces a trial starting during Roland Garros. He said recently he won't attend the start of the trial.
Zverev leads 4-2 in his career meetings with Jarry but the series is tied 2-2 on clay.
"Nicolas is one of the most aggressive players we have on the tour," Zverev said. "Obviously huge serve, huge forehand. Tries to hit big from both sides of the court."
The 32nd-ranked Tabilo eliminated top-ranked Djokovic in the third round on Sunday and hadn't dropped a set in the tournament until errors helped Zverev win the second-set tiebreaker. Zverev then took control early in the third.
The left-handed Tabilo saved a break point midway through the first set with a slicing serve out wide before producing three drop shots to serve out the set.
11°C