Germany's Julia Görges made the third round after winning in three sets, but it was Jan-Lennard Struff who stole the show for German tennis.
Raonic reached the third round for a sixth straight year, having lost to eventual champion Roger Federer in last year's quarter-finals.
Federer delivered a Centre Court masterclass lasting 89 minutes as the Swiss star hit 48 winners and 16 aces in his 6-4, 6-4, 6-1 victory.
In his 20th Wimbledon appearance, top seed Federer, a 20-time Major victor, is bidding to become only the second player to claim nine singles titles at the All England Club after Martina Navratilova.
"I'm happy to be back at Wimbledon. It will be much more of a strategic match, I believe, the way Mannarino plays", Federer said. I created more chances in the second set and was always able to stay pretty clean on my own service game.
Wozniacki is still waiting to get past the round of 16 for the first time, despite fighting back from 5-1 down in the third set and saving four match points at 5-3.
Five-time champion Venus overcame a slow start to defeat Romanian qualifier Dulgheru 4-6 6-0 6-1 in almost two hours for her 89th match victory at Wimbledon.
Agassi, a victor of eight grand slam titles in a stellar career, is at a loss to explain Federer's incredible achievements. It's about how many years have been playing at the top level.
Federer did not oblige, but moments later, he did lose a point he served at 4-1, 30-love, when Lacko smacked a down-the-line backhand passing victor.
The next day of the Wimbledon tournament was not completed due to rain. It's just about winning the match.
Winning 6-4, 6-4, 6-1 in 90 minutes, Federer showcased the best of his talents as he kept Lacko at arm's length with his impressive range of shots.
The 27-year-old second seed was also plagued by a barrage of flying ants during Wednesday's match on Court One, and needed insect repellent to get rid of them.
Very little did not work on this day, and he's allowed his two opponents to collect a total of 17 games through six sets. "If that's your best or not doesn't matter".
The 36-year-old kicked off his third major of the season with a bang as he registered a crushing 6-1, 6-3, 6-4 win over Serbia's Dusan Lajovic in a one-sided opening round clash.
Dutchwoman Kiki Bertens is also through with a 6-4, 6-0 result against Russian Anna Blinkova, but Poland's Agnieszka Radwanska is out following a 7-5, 6-4 loss to Czech Lucie Safarova.
Seven-time champion Serena fired 24 winners past Bulgarian Tomova to post a convincing 6-1 6-4 victory in 66 minutes on Centre Court.