Having taken over from Steve Bruce with Sunderland in a similar position, O'Neill made an instant impact and appeared to have turned things around, but the end of the campaign was tough and they have carried on in the same vein this season.
The Black Cats head into Saturday's home clash with the Blues having won only two of their last 22 league games and stuck one point above the relegation zone.
But O'Neill remains confident there are much better times ahead, and he has the experience to back it up.
He said: "I've been in management 20 years. I've had tougher times at other clubs and we've come through them. When I went to Leicester City, the first 10 or 11 games I couldn't win a match to save my life.
"We turned that round and were pretty successful.
"The first year at Aston Villa was exceptionally tough indeed. We'll pull round and, inevitably I hope, we'll get a team that the supporters are really proud of.
"It's been a tough start to the season. It hasn't come as any major surprise to me. The team is essentially the same as last season so it's a tough struggle, but we'll get there."
As well as his own experience, O'Neill also believes last season's struggles put Sunderland in a good position to turn things around. He said: "There's lots of elements attached to this. The unity is very important of course but the players this time last year were in a similar position so we've got a bit of experience of that.
"We'd obviously hope that experience plus the spirit that exists in the squad would give us a headstart."
Defender John O'Shea and striker Steven Fletcher are both in contention.
O'Shea is the more likely to feature having trained this week following a calf injury, while leading scorer Fletcher will be assessed on Friday.
The Scot was forced off at half-time in last weekend's defeat by Norwich with an ankle problem and saw a specialist this week.
Captain Lee Cattermole is expected to be out for another two months after damaging knee ligaments.
Chelsea received mixed news on the injury front with John Terry's unavailability for the FIFA Club World Cup tempered by the imminent return of Frank Lampard.
Terry has been advised against travelling to the tournament in Japan due to the possibility that his recovery from knee ligament damage may be hampered by inflammation during the 12-and-a-half hour flight.
Interim manager Rafael Benitez has refused to set a date for his comeback, but was able to confirm that Lampard will participate in Saturday's Barclays Premier League clash with Sunderland.
Lampard has been sidelined since October with a calf problem but has been passed fit, while Daniel Sturridge could feature in the Club World Cup but will not play at the Stadium of Light following his battle with a hamstring injury.
Chelsea depart for Japan on Saturday evening and while Benitez admitted Terry was disappointed to have missed out, he understands his rehabilitation requires patience.
"John was quite excited about the competition because it was something different and a great opportunity," the Spaniard said.
"But we had to be cautious because of his knee problem. He wanted to go and to help, but it's better that he stays.
"We don't know when he'll play. With this type of problem you have to wait and see how he reacts.
"He's training very hard, but knees are a special case because it's not muscle there are lots of joints to fix. He knows we have to be patient."
PREVIOUS MEETINGS
Chelsea 1-0 Sunderland 14/01/2012
Sunderland 1-2 Chelsea 10/09/2011
Sunderland 2-4 Chelsea 01/02/2011
Chelsea 0-3 Sunderland 14/11/2010
Chelsea 7-2 Sunderland 16/01/2010
Sunderland 1-3 Chelsea 18/08/2009
PREDICTION
Sunderland 1-3 Chelsea
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Source: DSG
Source: DSG