The Indians may have lost Ishant Sharma, one of their only two pace bowlers, after he complained of a knee problem and was taken to hospital for scans.
Ishant had looked out of sorts in bowling eight no balls, including four in one over.
"Who knows exactly what's happening with Ishant Sharma, but there's no doubt that unfortunately when a bowler does go down it means there's a lot more pressure physically on the other bowlers," said Watson after scoring his second Test hundred.
"There's no doubt we have to make the most of that slight advantage you do have and I suppose that is the only downfall of playing two spinners and two quicks, the unfortunate thing that might happen like today puts a lot of pressure on the other bowlers.
"But they do have Virender Sehwag, who did get six wickets in Delhi two years ago."
Watson (101no) also defended his captain Ricky Ponting (71) after an ugly confrontation with the Indian paceman Zaheer Khan (3-45), following the run out that proved to be the turning point of the day's play.
"As you did see on the footage, everyone knows exactly how Ricky is, and he's not going to go really looking for a fight," said Watson.
"Unless someone steps out of line out of the huddle and has a bit to say, and that's exactly what everyone was able to see, so Ricky's a very proud person and he knows how important it is as Australian captain to not get involved in situations.
"Everyone saw the footage so everyone knows exactly what happened."
Zaheer was spoken to by match referee Chris Broad after play.
Watson will resume alongside wicketkeeper Tim Paine, who was unbeaten on a nervous one not out overnight.
