Jaziri, ranked 128th in the world, had not played a match on the ATP Tour for six months but that did not stop him snatching the first set from the 17-times Grand Slam champion.
After watching Swiss Federer squander three break points in the opening set, Jaziri could barely believe his eyes when his more celebrated opponent slapped the ball into the net to go a break down at 5-6.
Jaziri, 29, made sure his bragging rights did not end there as he took the first set with a rip-roaring backhand down the line passing shot winner that left Federer flat-footed and the fans sensing a night-time upset.
However, if Jaziri started to wonder what it would feel like to beat a champion like Federer, those dreams were brutally snuffed out as the second seed exacted revenge by racing through the next two sets.
On a relatively low-key opening day, seventh seed Andreas Seppi beat Frenchman Paul-Henri Mathieu 6-3 7-5 and Russian eighth seed Mikhail Youzhny overcame Slovenia's Blaz Kavcic 1-6 6-1 6-3.
Top seed Novak Djokovic was in action on day one with his brother Marko but their doubles adventure ended in round one. They were beaten 4-6 6-3 10-4 by Nikolay Davydenko and Dick Norman.
Sam Querrey battered fellow American Michael Russell in the first round of the Delray Beach International, blasting seven aces to take the first set 6-2 before his opponent retired with a leg injury at 2-2 in the second.
"I thought that was the best attitude I've had all year," third seed Querrey said. "I was hitting second serve returns and taking cracks at them, and dominating with my forehand. It's the most aggressive I've been all year."
Querrey, who lost in the second round in Memphis last week and has never got beyond the semis at the Delray, took just 44 minutes to wrap up his match against Russell.
Xavier Malisse, a Delray winner in 2005 and 2007, cruised past Alejandro Falla 6-3 6-3 while the upset of the day belonged to Ivan Dodig, who beat fifth seed Alexandr Dolgopolov 6-3 6-3.
"First few games I was struggling," Dodig said. "Coming from indoor to first tournament outdoor, every player is struggling a bit. It was a little strange."
In the day's other matches, Evgeny Donskoy beat Steve Darcis 7-6 6-3.
ATP Dubai results
Round 1
Somdev Devvarman (India) beat Igor Kunitsyn (Russia) 6-1 6-4
2-Roger Federer (Switzerland) beat Malek Jaziri (Tunisia) 5-7 6-0 6-2
8-Mikhail Youzhny (Russia) beat Blaz Kavcic (Slovenia) 1-6 6-1 6-3
Lukas Rosol (Czech Republic) beat Matteo Viola (Italy) 6-3 7-5
Daniel Brands (Germany) beat Florent Serra (France) 7-6(7) 6-4
Roberto Bautista (Spain) beat David Goffin (Belgium) 6-2 7-5
7-Andreas Seppi (Italy) beat Paul-Henri Mathieu (France) 6-3 7-5
Delray Beach International results
Round 1
3-Sam Querrey (U.S.) beat Michael Russell (U.S.) 6-2 2-2 (Russell retired)
Ivan Dodig (Croatia) beat 5-Alexandr Dolgopolov (Ukraine) 6-3 6-3
8-Xavier Malisse (Belgium) beat Alejandro Falla (Colombia) 6-3 6-3
Evgeny Donskoy (Russia) beat Steve Darcis (Belgium) 7-6(5) 6-3
Acapulco International results
Round 1
Leonardo Mayer (Argentina) beat Miguel Angel Reyes (Mexico) 6-0 7-6(6)
Santiago Giraldo (Colombia) beat Ruben Ramirez Hidalgo (Spain) 4-6 6-4 6-4
Joao Sousa (Portugal) beat 5-Jurgen Melzer (Austria) 6-4 6-3
Pablo Andujar (Spain) beat Dusan Lajovic (Serbia) 3-6 7-5 6-2
Martin Alund (Argentina) beat Daniel Garza (Mexico) 7-6(7) 7-5
