Alcaraz downs Bagnis in Miami opener, Zverev knocked out by wild card
Reigning US Open champion Alcaraz eased past Bagnis 6-0 6-2, firing 12 winners and three aces for the match, committing only 11 unforced errors.
The Spaniard won the first set in 24 minutes, marking the first time he has won an opening frame 6-0 at an ATP Masters 100 event. It was also the first bagel he has dished out since beating Bagnis in Umag last year.
"I knew that I needed to be focused for my first match," Alcaraz said after his win, having triumphed in Indian Wells last week. "To start a new tournament is never easy, different conditions.
"I have to be ready to get used to these new conditions, but I was really focused on the match from the beginning, and I'm happy with the way that I played. I try to improve every day."
Alcaraz will face Dusan Lajovic after he beat 30th seed Maxime Cressy 6-4 7-6 (7-2), having knocked off Andy Murray in the first round.
Zverev was the highest seed to bow out on Friday, going down 6-0 6-4 to Japan's Taro Daniel, who beat world number four Casper Ruud last month in Acapulco.
Daniel triumphed in 73 minutes against the German, hitting 17 winners and committing only two unforced errors for the match, while Zverev gave up 18.
The Japanese wild card will meet Emil Ruusuvuori in the third round after the Finn beat 22nd seed Roberto Bautista Agut 6-4 7-6 (7-5) to open up that section of the draw.
Third seed Ruud also had few problems getting past Ilya Ivashka 6-2 6-3 to set up a clash with Botic van de Zandschulp after his three-set win over Alexei Popyrin.
Sixth seed Andrey Rublev overcame J.J. Wolf 7-6 (7-3) 6-4, having been broken in the opening game of what was a tight contest.
Jannik Sinner beat Laslo Djere 6-4 6-2, marking his 16th win out of 20 appearances at the Sunshine Double (Indian Wells and Miami), with only three other players – Novak Djokovic, Alcaraz and Hubert Hurkacz – having as many wins within their first 20 matches.
Ninth seed Taylor Fritz defeated fellow American Emilio Nava 6-4 6-1, and will face Denis Shapovalov in round three after he beat Guido Pella 6-3 3-6 6-3.
American 16th seed Tommy Paul came from a set down to beat Marc-Andrea Huesler 5-7 6-3 6-4, while seventh seed Holger Rune beat Martin Fucsovics 6-3 7-5.