Lewis crossed a minute from time to earn Pontypridd's first victory in the Welsh Premier Division play-offs after Ebbw Vale looked to have stolen it with a 78th-minute drop goal by Jason Strange, who kicked a total of 18 points in the match.
Pontypridd were without their captain Neil Jenkins, who is still recovering from a shoulder operation, so their scrum-half Paul John wore the No 10 shirt and the wing Gareth Wyatt took over the kicking duties.
After trailing 18-8 at one stage, Pontypridd clawed their way back into the game with four second-half tries.
In the other play-offs, Bridgend won 28-18 at Newport and Caerphilly hammered Aberavon 65-13. Bridgend owed their success to two tries from their centre Gareth Jones and a superb 50-yard solo effort from their scrum-half Steve Wake. For Caerphilly, the former Wales centre Roger Bidgood claimed a hat-trick of touchdowns while their full-back Brett Davey clocked up 35 points.
Cardiff, who sat out this season's Premier Division campaign, went on the rampage with a 96-28, 16-try demolition of Richmond. Leading the way was Craig Morgan with four tries, Simon Hill with three and Liam Botham, who also kicked five conversions, Gregory Kacala and Phil Wheeler with two each.
Bristol improved their points difference lead over Rotherham in Allied Dunbar Premiership Two to +27 with a 44-13 win at Waterloo. But it looks as though they will need to beat Worcester, who lost 35-27 at home to Rotherham yesterday, in their final game next weekend at the Memorial Ground and hope that their Yorkshire rivals do not run up a cricket score against Moseley to lift the title and confirm their return to Premiership One. Blackheath moved off the bottom for the first time this season with a thrilling 27-26 victory in their final league fixture at Fylde who now prop up the table.
Cork Constitution beat Garryowen 14-11 after extra time in the AIB League final at Lansdowne Road. Only points difference, in Garryowen's favour, separated the teams at the end of the league season in which they filled the top two places.
Former New Zealand flanker Jamie Joseph, who was vilified for deliberately stamping on Kyran Bracken's ankle when playing against England at Twickenham in 1993, marked his international debut for Japan with a try in their 23-21 victory over Canada in Tokyo.Reuse content