Klaas-Jan Huntelaar struck a hat-trick, and missed a penalty, to go with Chinedu Obasi's second-half goal at the Veltins Arena in Gelsenkirchen.
Keller was delighted with his team, who had come into the clash on the back of a three-match winless run that included a 6-1 loss to Real Madrid and 5-1 defeat at the hands of Bayern Munich.
"I'd like to praise my team in the highest terms. They took a lot of criticism after the recent defeats and said they were out to show the right response against Hoffenheim," he said.
"They did that in impressive fashion. We pressed the ball very well and were very determined.
"Although we took an early lead we were always aware of the threat Hoffenheim pose. They have a very good forward line and so I would have preferred to have gone in at half-time 3-0 up but the 'Hunter' made amends for his penalty miss in the second half.
"I think the margin of victory was deserved."
Huntelaar tapped in Joel Matip's squared header on six minutes before drilling in Julian Draxler's pass from 18 yards just before the half-hour mark.
While the Dutchman was unable to complete his hat-trick when he failed to convert a penalty on 31 minutes, Obasi struck from distance early in the second half.
Huntelaar did get his third 11 minutes before full-time as he tapped in after a wonderful run by Draxler.
The 30-year-old preferred to focus on the efforts of his team despite his starring role in the victory, which put fourth-placed Schalke five points clear of Wolfsburg.
"It was a great game from every single one of us. We were aggressive and we dominated," Huntelaar said.
"We defended right up the field and didn't let Hoffenheim into the game. Maybe they had one or two chances but that was it."
Hoffenheim coach Markus Gisdol, whose side sit 10th in the Bundesliga, felt his team deserved better early in the encounter.
"We held our own in the first half an hour and were perhaps the better team but we still found ourselves two goals down," he said.
"Schalke took their chances with clinical efficiency. We were a bit more passive after that and our opponents made optimum use of their attacking strengths."
