There were several new faces making plays in Friday night's preseason opener as the Chiefs rookie class made their presence felt in all three phases in the loss to San Francisco.

Quarterback Patrick Mahomes  was particularly impressive in his professional debut, completing seven of nine passes for 49 yards and a touchdown. His 126.4 passer rating led all Chiefs quarterbacks.

"Adrenaline was pumping," Mahomes said. "You're living out a dream.  You're doing something you were imagining in backyards since you were a little kid. I definitely was excited."

Mahomes entered the game with 6:44 left in the second quarter and didn't waste any time getting comfortable, completing a 41-yard strike to wide receiver Demarcus Robinson on the first play of his career, but it was called back because of offensive holding.

Still, Mahomes appreciated the chance to show off his arm after quarterbacks Alex Smith and Tyler Bray both started their first drives with deep throws.

"Coach Reid asked me if I liked what I had seen from the other quarterbacks, and they both completed theirs, so I thought it was a good idea," Mahomes said. "We went out there and completed it, then just tried to build upon that every time."

Mahomes went on to play through the third quarter, throwing a 1-yard touchdown pass to fellow rookie Marcus Kemp with six minutes left in the third. The catch was Kemp's first in his professional career.

"(Kemp) was the third read," Mahomes said. "I rolled out and they had covered up the first two, so I tried to make something happen.  He adjusted really well.  I threw it back to him and he went up and got it."

Another rookie, running back Kareem Hunt, was largely responsible for setting up Mahomes' first professional score.

With San Francisco punting from the Kansas City 42-yard line, newly acquired linebacker Kevin Pierre-Louis beat his man off the edge and blocked the punt. Hunt scrambled after the ball and returned it 12 yards to the San Francisco 8-yard line before being tripped up. The play set up Mahomes' score three plays later.

"Honestly, I was just trying to make a play and get some points on the board," Hunt said. "I was trying to scoop and score it, but I recovered it and that was the most important thing."

Hunt's hustle on special teams didn't go unnoticed.

"I would have liked to have gotten him going on the offensive side, but he did a nice job there and that's a plus," said Chiefs head coach Andy Reid. "You need your backup running backs to be good special teamers. He really did a nice job with it."

Hunt wasn't the only rookie to make a play on special teams, as defensive lineman Ricky Ali'ifua blocked a 51-yard field goal attempt in the closing seconds of the first half. Ali'ifua was signed as an undrafted free agent out of Utah State.

Rookie wide receiver Gehrig Dieter, an undrafted free agent out of the University of Alabama, added a 16-yard catch on what was a largely successful showing for the newest Chiefs.

On the defensive side of the ball, rookie linebacker Ukeme Eligwe tallied five tackles (3 solo), tying for the team lead. Eligwe was the Chiefs fifth round selection in the 2017 Draft out of Georgia Southern.

"(Eligwe) got a lot of snaps," Reid said. "There's some good stuff that he can take out of that."

Reid also mentioned defensive lineman Tanoh Kpassagnon and wide receiver Jehu Chesson as rookies that had productive nights on Friday, even if they didn't fill up the stat sheet.

Kpassagnon, the Chiefs second round pick out of Villanova, played 49 snaps on defense, the second-most of any Chiefs defensive player.

"I thought (Kpassagnon) played well, we asked him to play three different positions – he was a rush end, an outside linebacker and then we kicked him inside on a few snaps," Reid said. "He was all over the place and did a pretty good job."

Chesson, a fourth round selection out of Michigan, returned three kicks for 78 yards, including a 39-yard return in the second quarter.   

Overall, Reid was impressed with how his rookie class handled the moment, but stressed they still have a way to go.

"They have plenty of room to grow," Reid said. "But they tried their tails off and did some good things."

Catch the rookies and the rest of the Chiefs on August 19 at 6 p.m. on KCTV5 as Kansas City travels to Cincinnati to take on the Bengals in the second week of preseason action.