But that was then and this is now.
For the day, he completed 16 of 27 passes for 250 yards to go along with those touchdowns. He was erratic early in the game throwing a needless interception when he missed a wide-open Dwayne Bowe.
But for the second straight week, he elevated his game to a new level in the second half. Last weekend at Cleveland he directed two drives that resulted in a pair of field goals to defeat the Browns 16-14.
On Sunday afternoon against the leagues fourth best defense, he shredded the 49ers in the second half by throwing a pair of picture perfect touchdowns.
The first in the third quarter came on a trick play. Running Back Thomas Jones lined up in the wildcat formation. After he received the ball from center, wide receiver Dexter McCluster came in front of Jones and took a hand off from Jones.
On the play the 49ers paid no attention to Cassel who was lined up at wide receiver. As McCluster flew across the field, Cassel took a flea-flicker pitch from McCluster and then sent a perfect strike to Chiefs wide receiver Dwayne Bowe for his second touchdown pass of the game.
Chiefs Wide Receiver Dwayne Bowe finished a perfectly executed flea-flicker.
But in order for this play to work, Bowe couldn't break for end zone too soon. At the point that McCluster moved across the field he did a post pattern that resulted in a 45-yard touchdown.
Based on his recent performance, you'd think that two touchdown passes would have been enough for Cassel. But he wasn't done. In the first quarter, he hit McCluster for a 31-yard touchdown.
To cap off a brilliant day, he capped off an eight play, 61-yard drive by throwing a dart to rookie Tight End Tony Moeaki.
Oh yeah did we forget to mention that the rookie from Iowa hauled in Cassel's high throw with just one hand in the back of the end zone. It was Otis Taylor-esque. Even more important for this franchise - it was Tony Gonzalez-esque.
That touchdown brought down the Arrowhead house and Cassel's Hat Trick was more than enough for the Chiefs to win their third straight game to open the 2010 campaign.
This win should serve Cassel and his teammates well heading into the bye week as they shake that losers mentality that had framed this franchise for most of the past decade.
The Chiefs set the standard for losses the last four seasons. Now they're winning as a team and that's not lost on the Chiefs quarterback.
"Winning ball games is what the NFL is all about," he said after the win. "There are a lot of guys in this locker room that had a tough year last year."
Chiefs Tight End Tony Moeaki gets his first NFL touchdown late in the second quarter.
And he's correct. This team only managed four victories last season with Cassel at the helm. With one more win over the next 13 weeks, he can match that total.
But to keep it up, Cassel just has to manage the offense and keep opposing defenses on their toes. He doesn't have to be brilliant each week not when you can rush for over 200 yards per game.
"We're playing well right now. The balanced attack keeps the defense guessing," he said.
Still Cassel has taken his share of abuse from the fan base and probably even more so from his coaching staff. At times, he has looked awful. On the flip side, like his play in the second half, he plays like a man capable of leading his team into the playoffs.
But despite the 3-0 record, don't think for a second that he's satisfied.
"We're going to keep working. We've had a little success. We have to continue to build off this performance," Cassel said.
And with two weeks to prepare for Indianapolis, this team could be in for even greater heights should they be able to go on the road and defeat the Colts.
At one point that never seemed possible. But after starting 3-0, Cassel and his teammates aren't taking anything for granted.
"We're going to enjoy this one. We're not going to be happy. We're just going to keep working," Cassel said.
And with that confident workmanlike attitude, Cassel could lead his Chiefs to even more wins in the weeks ahead.