Leinster overturned a half-time deficit to edge the Dragons 23-17 in a nail-biting Pro12 clash at Rodney Parade on Friday.
Leinster made it seven wins in a row over but were made to work very hard in Wales.
Second-half tries from Aaron Dundon and Noel Reid inside the space of four minutes, while the Dragons were down to 14 men, turned the game in the Irish side's favour after they had trailed 10-6 at the interval.
Jimmy Gopperth supplied the rest of their points from the kicking tee.
Following a lacklustre opening half an hour which saw Tom Prydie and Gopperth trade penalties, the game suddenly sprung into life with the Dragons first denying Leinster and then scoring a fantastic try themselves.
Prydie pulled off a brilliant cover tackle to force Reid into touch inches from the line just as the centre passed inside to Gopperth, and was then involved in a free-flowing backs move that resulted in Ross Wardle scoring the first try of the night.
Tovey nailed the touchline conversion before Gopperth kicked his second penalty of the match on the stroke of half-time to make it 10-6 to the Dragons.
After a penalty apiece for Tovey and Gopperth disaster struck the Dragons when they lost lock Adam Jones for 10 minutes for taking a man out in the air.
Champions Leinster showed their ruthless streak to score 14 unanswered points during that period, hooker Dundon being driven over from close range before Reid profited from Zane Kirchner's fine break to score the Irish side's second try of the night.
Tovey kicked a penalty and then added another three points with the boot after Leinster lost replacement forward Jack O'Connell to the sin-bin for playing the ball illegally at the ruck.
Dragons almost snatched it at the death when Dan Evans' chip ahead forced Luke Fitzgerald to take the ball over his own line. But the Dragons made a mess of controlling the ball at the base of a second re-set five-metre scrum to allow Leister off the hook.
Pens: Prydie, Tovey 3
Yellow card: A. Jones
Tries: Dundon, Reid
Cons: Gopperth 2
Pens: Gopperth 3
Yellow card: O'Connell
Dragons: 15 Hallam Amos, 14 Tom Prydie, 13 Pat Leach, 12 Ross Wardle, 11 Adam Hughes, 10 Jason Tovey, 9 Richie Rees, 8 Netani Talei. 7 Lewis Evans (c), 6 Jevon Groves, 5 Matthew Screech, 4 Adam Jones, 3 Dan Way, 2 Sam Parry, 1 Owen Evans.
Replacements: 16 Hugh Gustafson, 17 Nathan Williams, 18 Francisco Chaparro, 19 Rob Sidoli, 20 Ieuan Jones, 21 Jonathan Evans, 22 Kris Burton, 23 Dan Evans.
Leinster: 15 Zane Kirchner, 14 Darragh Fanning, 13 Luke Fitzgerald, 12 Noel Reid, 11 Lote Tuqiri, 10 Jimmy Gopperth, 9 John Cooney, 8 Rhys Ruddock, 7 Shane Jennings (c), 6 Dominic Ryan, 5 Tom Denton, 4 Quinn Roux, 3 Martin Moore, 2 Aaron Dundon, 1 Michael Bent.
Replacements: 16 James Tracy, 17 Jack O'Connell, 18 Tadhg Furlong, 19 Ben Marshall, 20 Leo Auva'a, 21 Luke McGrath, 22 Cathal Marsh, 23 Brendan Macken.
Venue: Rodney Parade
Referee: John Lacey (Ireland)
Assistant referees: Ian Davies, Neil Hennessy