The Serb, seeking his third title at the event having triumphed in 2011 and 2016, won 6-4, 6-2 on the Manolo Santana court at La Caja Mágica.

Djokovic broke Fritz’s serve once in the first set and twice in the second to begin his campaign at the Association of Tennis Professionals (ATP) World Tour Masters 1000 event in successful fashion.

"I thought it was a solid match," Djokovic told the ATP.

"At 3-3 in the first set, when I broke, that was the turning point.

"And probably the next game, saving break point after a long rally where I was defending, I was lucky he missed a shot.

"After that I started to swing through the ball a little bit more. 

"I think Taylor wasn’t at his best, struggling physically or health-wise.

"But in general it is a good lead in a good opening match and, hopefully, it can only get better from here."

Next up for Djokovic is the winner of tomorrow's match between France's Jérémy Chardy and Argentina's Diego Schwartzman.

Also through to the last 16 is 20-time Grand Slam winner Roger Federer as the Swiss marked his first match on clay since the Rome Masters in May 2016 by defeating France's Richard Gasquet 6-2, 6-3.

It secured the world number three his 19th win in 21 outings this season.

Elsewhere, fifth seed Dominic Thiem of Austria advanced after American opponent Reilly Opelka was forced to retire due to injury. 

Thiem, the winner at last month's Barcelona Open, was leading 6-7, 6-3, 1-0 when Opelka pulled out.

Ninth seed Marin Čilić, meanwhile, continued his progress with a 4-6, 6-3, 6-4 victory over Germany's Jan-Lennard Struff.

In the Women's Tennis Association Premier Mandatory event, top seed Naomi Osaka booked her place in the last 16 with a 7-6, 3-6, 6-0 win at the expense of Spain's Sara Sorribes Tormo.

That set up a meeting with Belarus' Aliaksandra Sasnovich, who overcame Slovakia's Anna Karolína Schmiedlová 6-2, 6-2. 

Third-seeded Romanian Simona Halep, the 2016 and 2017 champion, is also through to the next stage after beating Great Britain's Johanna Konta 7-5, 6-1.

Away from the court, fourth seed Angelique Kerber of Germany has announced her withdrawal from the event due to an ankle injury suffered in practice today.

There was a shock loss, meanwhile, for fifth-seeded Czech Karolína Plíšková, who fell to a 5-7, 6-2, 4-6 defeat at the hands of Ukraine's Kateryna Kozlova.