Northamptonshire pulled off a run-chase to beat Surrey while Durham won on the final day of their Division Two match.
Northants, who resumed on 106-2, chased down 320 with just two wickets remaining after an innings of 99 from Rob Keogh and Luke Procter's 57.
Durham took 10 overs to take the three wickets they required to beat Glamorgan by an innings and 42 runs.
In Division Three, Derbyshire drew with Leicestershire and Sussex were forced to follow on by Middlesex at Hove.
Sussex captain Tom Haines hit a career-best 156 as the hosts were bowled out for 319 on day three, and they were 88-3 at the close, still 269 runs behind Middlesex's first-innings total of 676-5 declared.
The final day was well poised at Northampton, and Northamptonshire pulled off a thrilling chase.
The hosts lost Emilio Gay for 50 but a solid partnership between Keogh and Proctor saw them past 200 before Keogh fell agonisingly short of his century when he was caught off Jordan Clark at mid-wicket.
Proctor and Rossington (32) guided Northants to 271-4 but, after the new ball was taken, both men departed in the space of five deliveries before tea, and Surrey had renewed hope when the wicket of Saif Zaib left the hosts on 287-7.
Tom Taylor then dragged Northants to the cusp of victory, but he was brilliantly caught for 25 down the leg side by wicketkeeper Jamie Smith off Jordan Clark (5-76) with just two runs required.
However, first-class debutant James Sales - the son of former Northants captain David Sales - hit the winning runs when he pulled Cameron Steel to the boundary.
At Chester-le-Street, Durham took little time to see off Glamorgan.
The hosts had been stalled by a 163-run seventh-wicket stand on day three but closed out a big win before lunch as Glamorgan added 31 runs to their overnight total of 333-7.
The first breakthrough came when Andrew Salter edged Paul Coughlin behind for a career-best 90 and Chris Rushworth then clean bowled Lukas Carey for a duck.
Coughlin then ended the contest by removing Michael Hogan to finish with 5-64, and match figures of 9-75, on his return from injury.
Leicestershire managed to enforce the follow-on in the morning session at Derbyshire, but Billy Godleman's unbeaten century helped the hosts to salvage a draw.
Derbyshire were bowled out for 340, having added 27 runs to their overnight score and seen their final-wicket partnership dig in for 13 overs, but still trailed the Foxes by 188 runs.
Tom Wood edged Chris Wright behind from the second ball of the second innings, and the seamer also had Leus du Plooy caught behind to leave the hosts 18-2.
Wright then removed Wayne Madsen but Godleman and Matthew Critchley (59 not out) came together with an unbroken fourth-wicket partnership of 139.
And, after Godleman reached his century - his first of the season, which included 13 fours - Derbyshire had edged 15 runs in front and the two sides shook hands to bring the final session to an early close.
On day three at Hove, Sussex resumed on 103 without loss but opener Ali Orr edged Blake Cullen behind from the seventh ball of the day.
Tom Haines passed his century in a 118-run partnership with Ben Brown before Brown was stumped on 80 off the bowling of Luke Hollman.
On a flat pitch, Middlesex then began to take wickets regularly and Sussex lost their final six wickets for 12 runs as Hollman (5-65) registered his maiden five-wicket Championship haul.
Still ahead by 357 runs, Middlesex captain Tim Murtagh enforced the follow-on and the visitors managed to pick up three wickets before the close.
Hollman got two of them, bowling Ali Orr for 20 and then having Ben Brown stumped, and nightwatchman Sean Hunt lasted 13 balls before he was trapped lbw by the part-time leg-spin of Sam Robson.
Captain Haines was left on 39 not out - and 18 runs shy of becoming the first batsman to reach 1,000 Championship runs this season - but his side are facing an uphill battle to salvage a draw on the final day.
Day Four scoreboards
Chester-le-Street: Glamorgan 97 & 364 (Douthwaite 96, Salter 90, Rutherford 71; Coughlin 5-64) v Durham 503-8 dec (Jones 81, Raine 74, Trevaskis 55*). Durham won by an innings and 42 runs.
Northampton: Surrey 252 & 238 (Jacks 50; Kerrigan 4-36) v Northamptonshire 171 & 322-8 (Keogh 99, Procter 57, Gay 50; Clark 5-76). Northamptonshire won by two wickets.
Derby: Leicestershire 528 (Hill 113) v Derbyshire 340 (Guest 116, Dal 106) & 203-3 (Godleman 100*, Critchley 59*). Derbyshire drew with Leicestershire.
Hove (day three): Middlesex 676-5 dec (Robson 253, Stoneman 174, White 110*, Andersson 88) v Sussex 319 (Haines 156, Brown 80; Hollman 5-65) & 88-3 (Haines 39*; Hollman 2-16).