England had not won in Dublin for 10 years before the weekend, the 2003 victory coming in the same year that they won their first and only World Cup before a painfully long title drought that ended at the 2011 Six Nations.
"This was a victory that felt like a watershed moment for this team," Robshaw wrote in his Daily Telegraph column on Monday.
"It may not have been a day for attacking rugby but it was all about territory and defence and putting Owen Farrell in the right position to kick goals."
Another assured performance from flyhalf Farrell brought the 21-year-old all 12 points in the greasy conditions in Dublin and won the England man more admirers, though Robshaw hailed the team's defensive qualities and discipline.
England lost forward James Haskell for 10 minutes in the second half when he was sin-binned and, with Ireland and their vociferous support re-energised at that point as they pulled level from the resulting penalty, the visitors' defence went into overdrive.
"It was about expecting the unexpected and taking the energy out of the Irish attack," said Robshaw.
"Our defence was brilliant. To keep pressuring them and knocking them back was what we wanted and critically we were able to outscore Ireland during James's absence."
Robshaw said England had been warned about sitting back, which they did two years ago in a 24-8 defeat, so they came to Dublin to impose themselves.
"We wanted to put down a marker and our message to the team before kick-off was: 'no backward step' and I think we did that."
Equally pleasing for England was the strength of the replacements bench, highlighted after halftime when coach Stuart Lancaster brought on Manu Tuilagi for Billy Twelvetrees at centre and Courtney Lawes for Joe Launchbury at lock.
There was still a long way to go, however, warned Robshaw, confirmed by a look at the remaining fixtures for the championship pacesetters.
Next up, England welcome France in London on Feb. 23, before they host Italy on March 10 and face a tricky trip to holders Wales on March 16.
"We know we still have three massive games to go and I know our coaching group will keep our feet on the ground and not let us look too far ahead," said Robshaw.
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