Smith was fastest in the heats and had already won the Scottish title last Sunday to claim his place in Team Scotland. Five days later and he posted a faster time (4:15.76) - but had to settle for silver to Pavoni's 4:12.24.
It was a personal best for the 23-year-old Englishman, who had his parents and his brother in the crowd for support. "The last time I did a PB was at the 2012 Olympic trials and that seems a long time ago," said the Loughborough swimmer. "I swam in the Duel in the Pool here in December and that was the best meet ever. Now it's nice to have my name on the Commonwealth Games list and be ready to come back this summer."
For Smith, it was another move in the right direction. "It felt better than last week but I still want to go faster," said the University of Stirling 26-year-old. "I am also going to try and get a 200m medley qualifying time."
Warrender's Craig Benson handed himself a Games lifeline. At last week's Scottish Championships, the 19-year-old finished third in the final in 1:01.58, 0.01sec outside the standard. He clocked a quicker 1:01.42 and now needs a repeat in tonight's final to claim his 2014 berth. Benson was just 17 when he qualified for the London Olympics and it would be heartbreaking for the youngster if he didn't make it to his home Commonwealths.
Ross Murdoch, the Scottish record holder, won his semi-final in 1:00.16, ahead of Olympic silver medallist, Michael Jamieson (1:00.85). Adam Peaty won the other semi in a swift 59.83sec.
England's James Guy, who had set a British record in the 400m on Thursday, added another gold in the 200m freestyle, although his time of 1:47.54 was almost a second slower than Robbie Renwick's Scottish Championship victory.
"It's nice to be a double British champion but I am a little disappointed that I didn't go faster," said the 18-year-old European Junior champion. "But I am happy with my form for this time of year. There is plenty more speed to come."
Edinburgh University's Corrie Scott, the Scottish champion, took the bronze medal in the 50m breaststroke. Scott's fellow Commonwealth Games qualifiers, Andrea Strachan (31.85sec) and Kathryn Johnstone (32.06sec), followed her home in fourth and fifth. The winner was England's Sophie Taylor, who set a new personal best of 30.98sec.
Scotland's Duncan Scott won the British Junior 200m freestyle and set a personal best of 1:49.88. It was his first swim under the magical 1:50.00 barrier and he finished more than a second ahead of Hatfield's Martyn Walton.