Last season’s Sky Bet Championship play-off finalists started the day in the relegation zone but they belied their lowly position on their way to a deserved win.
Substitute Mo Barrow, who failed to make an impact during a loan spell at Leeds last term, scored late on and Vito Mannone saved Pablo Hernandez’s stoppage-time penalty to inflict a third straight defeat on the early pacesetters.
The win moved Reading up to 20th in the table and with the likes of Middlesbrough, Sheffield Wednesday and Hull all in mid-table, Stam believes the Championship is as tough as ever.
“You’ve probably got 10 teams going for the two (automatic) promotion positions and if you look at the money spent in the summer as well, it’s tremendous,” said the Royals boss.
“It’s more competitive than even last season and it’s going to be very hard to end up in that top six.”
Stam’s side were full value for their win at Elland Road after carving out the best opportunities against a Leeds side still low on confidence despite the two-week international break.
Andy Lonergan, making the first league start of his second spell at the club, had kept United in the game only for Barrow to slide a shot under him six minutes from time.
Leeds were handed a lifeline in the dying minutes when Samuel Saiz was felled in the penalty area but Stam felt justice was done as Mannone guessed the right way to keep out Hernandez’s weak spot-kick.
“We had the better chances and deserved to win,” said Stam.
“You don’t always get what you deserve and you know if you don’t score your opportunities it’s going to be difficult when you’re playing against a very good team.
“But if you look at it overall we deserved to win in how we played. We were very focused, very composed, sharp and created the better chances.
“We didn’t start the season well or have that bit of luck but that’s how it goes in football.
“But you’ve got to keep believing, working hard, being positive and then with the ability you have you get results.”
On match-winner Barrow, he added: “That’s how it goes. If you play against your former team you always want to do well.
“Mo is a player with tremendous pace and is always a threat going forward in one v ones.
“He’s got scoring ability as well. If you give him the right ball at the right time, he can finish it.”
Thomas Christiansen, who dropped goalkeeper Felix Wiedwald after his shaky performance in the 3-0 defeat at Sheffield Wednesday, insisted Leeds deserved at least a point.
“We created more opportunities than Reading in the second half and deserved much more than what we got,” said Christiansen.
“But when the ball doesn’t go in, it’s difficult to win.”