The Millers were competitive but were undone by Hal Robson-Kanu's second-half strike to leave them six points from safety with 13 games to go.
Here's four things we learned from the game.
Rotherham lose games they shouldn't
In the current climate Rotherham in the Championship are alway going to lose more games than they win and most people would accept that. With that being the case they can ill-afford to lose the matches where they are competing with the opposition and not being out-played. However, Tuesday's reverse at the Madejski Stadium was the latest example of the Millers being in a game, with little to choose between the two sides, but still coming out of it with defeat. It has happened far too often this season and has resulted in them losing 21 games - more than any side in the top six levels of English football. All too often they have been unable to tough it out and secure a point in games they should have. Nottingham Forest, Brentford, Wolves, Blackburn, Preston, Bolton and last night were all games where the Millers did enough to take a point but ended up with nothing. That soft underbelly is going to cost them their place in the league.
Going with a whimper
When Tony Stewart pressed the panic button after the defeat to Bolton, his grand plan was to bring Neil Warnock in to inspire a great escape. Well, three games into the veteran's 15-game brief and it has not had anything like the desired affect. In fact, their situation has got worse in a big way. When Neil Redfearn got the bullet after the Bolton defeat, the Millers were two points from safety and, although on the back of two unacceptable results, performances had been promising - they'd drawn at Cardiff in their last away game and spanked Brighton not so long before. Now they have drifted out to six points from safety, which would have been eight had it not been for a late Huddersfield goal at MK Dons, and not only that but their level of performance is not where it had been under Redfearn. This is not a side that is going down without a fight, this is a side that is going down with a whimper. Given the severity of their plight and the level of the opposition they were up against on Tuesday they should have been battering down in the final 20 minutes, yet they could not even muster an effort on target. On the last few weeks' evidence, the Millers are more likely to finish bottom of the league than get out of trouble.
Has Neil Warnock got the appetite?
If Warnock could have that pre-job meeting with Stewart on the M5 again, the outcome might well be different. There is a real sense that the 67-year-old had no idea what he was letting himself in for and his appetite for the job might not be what it was before he came in. Press conferences are ended after only three minutes or so, always in a rush to get back to Cornwall where his wife's health means he is spending half of the week at home. The content of his press conferences is not exuding a whole lot of positivity, either, with his short answers bereft of any analysis or real insight. There has been no rallying cries or nothing to make you believe he is really up for the fight. He has already admitted that he is struggling with the demands, revealing he slept over 10 hours last week after Thursday training and the talismanic Warnock that everyone was expecting has yet to reveal himself, bar a couple of touchline histrionics. Of course, it might be wholly different in the dressing room, where players have spoken of his positivity. Unfortunately, we are yet to see any rewards of it.
'We always get 'sh*t refs'
While Rotherham's soft underbelly saw them lose yet another game, things could have been different had the Millers been awarded a blatant penalty on the stroke of half-time. When Grant Ward's shot was blocked, the ball fell to Richie Smallwood, he took a touch to set himself up for a shot but appeared to be tripped by a Reading defender. It just looked clear-cut. When referee Kevin Johnson blew his whistle all of the Madejski Stadium were expecting him to point to the spot. However, after a delay Johnson incredibly pointed his arm in the other direction and booked Smallwood for theatrics. Smallwood, the most honest pro at the club, and his team-mates were apoplectic at the decision. Had Johnson ruled the incident differently then the Millers would have had a great opportunity to go in front at a vital time and the game would have played out very differently.
