A sparkling 148 from Australian opener Marcus Harris saw Gloucestershire fight back in style against Glamorgan to reach 373-5, a lead of 134 runs.

Ashes candidate Harris put on 161 for the first wicket with Chris Dent (78).

Miles Hammond chipped in with 58 as the visitors found batting far easier in their second innings and put the game back in the balance.

Honour was satisfied on both sides in the first 20 minutes of the day as Glamorgan secured their fourth batting point while Tom Price claimed the last two wickets to earn the extra bowling point, leaving Billy Root undefeated on 117.

But Harris and Dent set about reducing the deficit with gusto as they rattled along at almost five runs an over with Glamorgan’s medium-fast battery of bowlers looking innocuous as the pitch got slower.

Dent’s runs came off just 100 balls with scarcely a false shot before he mistimed a defensive push and chopped a ball onto his stumps from Timm van der Gugten, who was again the pick of the home seamers.

James Bracey (15) edged Harry Podmore to slip but the unruffled Harris pulled his 16th boundary to reach three figures off 161 balls.

Hammond joined Harris in a stand of 111 before the Australian fell leg-before, trying to reverse-sweep the occasional spin of Kiran Carlson, and Hammond missed an attempted pull off Dan Douthwaite.

But Glamorgan could not make significant inroads with the new ball as captain Graeme van Buuren (36 not out) and Ollie Price (31) extended the visitors’ lead well into three figures, with serious hopes of at least saving the game or possibly trying a declaration on the final day.

Gloucestershire’s Chris Dent told BBC Radio Bristol:

“We came into the day behind the game, but we knew if we could put some partnerships together we could get in this position.

“It’s going to be a big morning, whether we can set the game up for ourselves or whether things change round.

“It was a different wicket from the first day, we got going quickly and it was nice to get off to that good start. Marcus is in fantastic form, playing really well at the minute so it’s great to have a consistent performer like that on your team.

“It’s a good wicket but it’s starting to spin more, hopefully it’ll break up a bit and bring (spinner) Zafar (Gohar) into the game.”

Glamorgan’s Billy Root told BBC Sport Wales:

“It’s always nice to contribute to getting your side in front, especially this early in the season. It was nice to get a first innings-lead of 230-odd and then I thought the lads bowled really well all day since the wicket’s got a lot better since day one.

“Some credit to Gloucester as well, but I though we were incredible with the ball in the last session on a placid wicket.

“There’s a long way to go in this game but hopefully we can get a couple of wickets early and push towards that victory.

“We can chase anything, if we can restrict them to something before lunchtime we’ll have a go.”